aboutsummaryrefslogtreecommitdiffstats
path: root/Documentation/DocBook/drm.tmpl
blob: 9727594893760994fdd08895188ef51202c0786b (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
	"http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []>

<book id="drmDevelopersGuide">
  <bookinfo>
    <title>Linux DRM Developer's Guide</title>

    <authorgroup>
      <author>
	<firstname>Jesse</firstname>
	<surname>Barnes</surname>
	<contrib>Initial version</contrib>
	<affiliation>
	  <orgname>Intel Corporation</orgname>
	  <address>
	    <email>jesse.barnes@intel.com</email>
	  </address>
	</affiliation>
      </author>
      <author>
	<firstname>Laurent</firstname>
	<surname>Pinchart</surname>
	<contrib>Driver internals</contrib>
	<affiliation>
	  <orgname>Ideas on board SPRL</orgname>
	  <address>
	    <email>laurent.pinchart@ideasonboard.com</email>
	  </address>
	</affiliation>
      </author>
      <author>
	<firstname>Daniel</firstname>
	<surname>Vetter</surname>
	<contrib>Contributions all over the place</contrib>
	<affiliation>
	  <orgname>Intel Corporation</orgname>
	  <address>
	    <email>daniel.vetter@ffwll.ch</email>
	  </address>
	</affiliation>
      </author>
    </authorgroup>

    <copyright>
      <year>2008-2009</year>
      <year>2013-2014</year>
      <holder>Intel Corporation</holder>
    </copyright>
    <copyright>
      <year>2012</year>
      <holder>Laurent Pinchart</holder>
    </copyright>

    <legalnotice>
      <para>
	The contents of this file may be used under the terms of the GNU
	General Public License version 2 (the "GPL") as distributed in
	the kernel source COPYING file.
      </para>
    </legalnotice>

    <revhistory>
      <!-- Put document revisions here, newest first. -->
      <revision>
	<revnumber>1.0</revnumber>
	<date>2012-07-13</date>
	<authorinitials>LP</authorinitials>
	<revremark>Added extensive documentation about driver internals.
	</revremark>
      </revision>
    </revhistory>
  </bookinfo>

<toc></toc>

<part id="drmCore">
  <title>DRM Core</title>
  <partintro>
    <para>
      This first part of the DRM Developer's Guide documents core DRM code,
      helper libraries for writing drivers and generic userspace interfaces
      exposed by DRM drivers.
    </para>
  </partintro>

  <chapter id="drmIntroduction">
    <title>Introduction</title>
    <para>
      The Linux DRM layer contains code intended to support the needs
      of complex graphics devices, usually containing programmable
      pipelines well suited to 3D graphics acceleration.  Graphics
      drivers in the kernel may make use of DRM functions to make
      tasks like memory management, interrupt handling and DMA easier,
      and provide a uniform interface to applications.
    </para>
    <para>
      A note on versions: this guide covers features found in the DRM
      tree, including the TTM memory manager, output configuration and
      mode setting, and the new vblank internals, in addition to all
      the regular features found in current kernels.
    </para>
    <para>
      [Insert diagram of typical DRM stack here]
    </para>
  </chapter>

  <!-- Internals -->

  <chapter id="drmInternals">
    <title>DRM Internals</title>
    <para>
      This chapter documents DRM internals relevant to driver authors
      and developers working to add support for the latest features to
      existing drivers.
    </para>
    <para>
      First, we go over some typical driver initialization
      requirements, like setting up command buffers, creating an
      initial output configuration, and initializing core services.
      Subsequent sections cover core internals in more detail,
      providing implementation notes and examples.
    </para>
    <para>
      The DRM layer provides several services to graphics drivers,
      many of them driven by the application interfaces it provides
      through libdrm, the library that wraps most of the DRM ioctls.
      These include vblank event handling, memory
      management, output management, framebuffer management, command
      submission &amp; fencing, suspend/resume support, and DMA
      services.
    </para>

  <!-- Internals: driver init -->

  <sect1>
    <title>Driver Initialization</title>
    <para>
      At the core of every DRM driver is a <structname>drm_driver</structname>
      structure. Drivers typically statically initialize a drm_driver structure,
      and then pass it to one of the <function>drm_*_init()</function> functions
      to register it with the DRM subsystem.
    </para>
    <para>
      Newer drivers that no longer require a <structname>drm_bus</structname>
      structure can alternatively use the low-level device initialization and
      registration functions such as <function>drm_dev_alloc()</function> and
      <function>drm_dev_register()</function> directly.
    </para>
    <para>
      The <structname>drm_driver</structname> structure contains static
      information that describes the driver and features it supports, and
      pointers to methods that the DRM core will call to implement the DRM API.
      We will first go through the <structname>drm_driver</structname> static
      information fields, and will then describe individual operations in
      details as they get used in later sections.
    </para>
    <sect2>
      <title>Driver Information</title>
      <sect3>
        <title>Driver Features</title>
        <para>
          Drivers inform the DRM core about their requirements and supported
          features by setting appropriate flags in the
          <structfield>driver_features</structfield> field. Since those flags
          influence the DRM core behaviour since registration time, most of them
          must be set to registering the <structname>drm_driver</structname>
          instance.
        </para>
        <synopsis>u32 driver_features;</synopsis>
        <variablelist>
          <title>Driver Feature Flags</title>
          <varlistentry>
            <term>DRIVER_USE_AGP</term>
            <listitem><para>
              Driver uses AGP interface, the DRM core will manage AGP resources.
            </para></listitem>
          </varlistentry>
          <varlistentry>
            <term>DRIVER_REQUIRE_AGP</term>
            <listitem><para>
              Driver needs AGP interface to function. AGP initialization failure
              will become a fatal error.
            </para></listitem>
          </varlistentry>
          <varlistentry>
            <term>DRIVER_PCI_DMA</term>
            <listitem><para>
              Driver is capable of PCI DMA, mapping of PCI DMA buffers to
              userspace will be enabled. Deprecated.
            </para></listitem>
          </varlistentry>
          <varlistentry>
            <term>DRIVER_SG</term>
            <listitem><para>
              Driver can perform scatter/gather DMA, allocation and mapping of
              scatter/gather buffers will be enabled. Deprecated.
            </para></listitem>
          </varlistentry>
          <varlistentry>
            <term>DRIVER_HAVE_DMA</term>
            <listitem><para>
              Driver supports DMA, the userspace DMA API will be supported.
              Deprecated.
            </para></listitem>
          </varlistentry>
          <varlistentry>
            <term>DRIVER_HAVE_IRQ</term><term>DRIVER_IRQ_SHARED</term>
            <listitem><para>
              DRIVER_HAVE_IRQ indicates whether the driver has an IRQ handler
              managed by the DRM Core. The core will support simple IRQ handler
              installation when the flag is set. The installation process is
              described in <xref linkend="drm-irq-registration"/>.</para>
              <para>DRIVER_IRQ_SHARED indicates whether the device &amp; handler
              support shared IRQs (note that this is required of PCI  drivers).
            </para></listitem>
          </varlistentry>
          <varlistentry>
            <term>DRIVER_GEM</term>
            <listitem><para>
              Driver use the GEM memory manager.
            </para></listitem>
          </varlistentry>
          <varlistentry>
            <term>DRIVER_MODESET</term>
            <listitem><para>
              Driver supports mode setting interfaces (KMS).
            </para></listitem>
          </varlistentry>
          <varlistentry>
            <term>DRIVER_PRIME</term>
            <listitem><para>
              Driver implements DRM PRIME buffer sharing.
            </para></listitem>
          </varlistentry>
          <varlistentry>
            <term>DRIVER_RENDER</term>
            <listitem><para>
              Driver supports dedicated render nodes.
            </para></listitem>
          </varlistentry>
        </variablelist>
      </sect3>
      <sect3>
        <title>Major, Minor and Patchlevel</title>
        <synopsis>int major;
int minor;
int patchlevel;</synopsis>
        <para>
          The DRM core identifies driver versions by a major, minor and patch
          level triplet. The information is printed to the kernel log at
          initialization time and passed to userspace through the
          DRM_IOCTL_VERSION ioctl.
        </para>
        <para>
          The major and minor numbers are also used to verify the requested driver
          API version passed to DRM_IOCTL_SET_VERSION. When the driver API changes
          between minor versions, applications can call DRM_IOCTL_SET_VERSION to
          select a specific version of the API. If the requested major isn't equal
          to the driver major, or the requested minor is larger than the driver
          minor, the DRM_IOCTL_SET_VERSION call will return an error. Otherwise
          the driver's set_version() method will be called with the requested
          version.
        </para>
      </sect3>
      <sect3>
        <title>Name, Description and Date</title>
        <synopsis>char *name;
char *desc;
char *date;</synopsis>
        <para>
          The driver name is printed to the kernel log at initialization time,
          used for IRQ registration and passed to userspace through
          DRM_IOCTL_VERSION.
        </para>
        <para>
          The driver description is a purely informative string passed to
          userspace through the DRM_IOCTL_VERSION ioctl and otherwise unused by
          the kernel.
        </para>
        <para>
          The driver date, formatted as YYYYMMDD, is meant to identify the date of
          the latest modification to the driver. However, as most drivers fail to
          update it, its value is mostly useless. The DRM core prints it to the
          kernel log at initialization time and passes it to userspace through the
          DRM_IOCTL_VERSION ioctl.
        </para>
      </sect3>
    </sect2>
    <sect2>
      <title>Device Registration</title>
      <para>
        A number of functions are provided to help with device registration.
        The functions deal with PCI, USB and platform devices, respectively.
      </para>
!Edrivers/gpu/drm/drm_pci.c
!Edrivers/gpu/drm/drm_usb.c
!Edrivers/gpu/drm/drm_platform.c
      <para>
        New drivers that no longer rely on the services provided by the
        <structname>drm_bus</structname> structure can call the low-level
        device registration functions directly. The
        <function>drm_dev_alloc()</function> function can be used to allocate
        and initialize a new <structname>drm_device</structname> structure.
        Drivers will typically want to perform some additional setup on this
        structure, such as allocating driver-specific data and storing a
        pointer to it in the DRM device's <structfield>dev_private</structfield>
        field. Drivers should also set the device's unique name using the
        <function>drm_dev_set_unique()</function> function. After it has been
        set up a device can be registered with the DRM subsystem by calling
        <function>drm_dev_register()</function>. This will cause the device to
        be exposed to userspace and will call the driver's
        <structfield>.load()</structfield> implementation. When a device is
        removed, the DRM device can safely be unregistered and freed by calling
        <function>drm_dev_unregister()</function> followed by a call to
        <function>drm_dev_unref()</function>.
      </para>
!Edrivers/gpu/drm/drm_stub.c
    </sect2>
    <sect2>
      <title>Driver Load</title>
      <para>
        The <methodname>load</methodname> method is the driver and device
        initialization entry point. The method is responsible for allocating and
	initializing driver private data, performing resource allocation and
	mapping (e.g. acquiring
        clocks, mapping registers or allocating command buffers), initializing
        the memory manager (<xref linkend="drm-memory-management"/>), installing
        the IRQ handler (<xref linkend="drm-irq-registration"/>), setting up
        vertical blanking handling (<xref linkend="drm-vertical-blank"/>), mode
	setting (<xref linkend="drm-mode-setting"/>) and initial output
	configuration (<xref linkend="drm-kms-init"/>).
      </para>
      <note><para>
        If compatibility is a concern (e.g. with drivers converted over from
        User Mode Setting to Kernel Mode Setting), care must be taken to prevent
        device initialization and control that is incompatible with currently
        active userspace drivers. For instance, if user level mode setting
        drivers are in use, it would be problematic to perform output discovery
        &amp; configuration at load time. Likewise, if user-level drivers
        unaware of memory management are in use, memory management and command
        buffer setup may need to be omitted. These requirements are
        driver-specific, and care needs to be taken to keep both old and new
        applications and libraries working.
      </para></note>
      <synopsis>int (*load) (struct drm_device *, unsigned long flags);</synopsis>
      <para>
        The method takes two arguments, a pointer to the newly created
	<structname>drm_device</structname> and flags. The flags are used to
	pass the <structfield>driver_data</structfield> field of the device id
	corresponding to the device passed to <function>drm_*_init()</function>.
	Only PCI devices currently use this, USB and platform DRM drivers have
	their <methodname>load</methodname> method called with flags to 0.
      </para>
      <sect3>
        <title>Driver Private Data</title>
        <para>
          The driver private hangs off the main
          <structname>drm_device</structname> structure and can be used for
          tracking various device-specific bits of information, like register
          offsets, command buffer status, register state for suspend/resume, etc.
          At load time, a driver may simply allocate one and set
          <structname>drm_device</structname>.<structfield>dev_priv</structfield>
          appropriately; it should be freed and
          <structname>drm_device</structname>.<structfield>dev_priv</structfield>
          set to NULL when the driver is unloaded.
        </para>
      </sect3>
      <sect3 id="drm-irq-registration">
        <title>IRQ Registration</title>
        <para>
          The DRM core tries to facilitate IRQ handler registration and
          unregistration by providing <function>drm_irq_install</function> and
          <function>drm_irq_uninstall</function> functions. Those functions only
          support a single interrupt per device, devices that use more than one
          IRQs need to be handled manually.
        </para>
        <sect4>
          <title>Managed IRQ Registration</title>
          <para>
            <function>drm_irq_install</function> starts by calling the
            <methodname>irq_preinstall</methodname> driver operation. The operation
            is optional and must make sure that the interrupt will not get fired by
            clearing all pending interrupt flags or disabling the interrupt.
          </para>
          <para>
            The passed-in IRQ will then be requested by a call to
            <function>request_irq</function>. If the DRIVER_IRQ_SHARED driver
            feature flag is set, a shared (IRQF_SHARED) IRQ handler will be
            requested.
          </para>
          <para>
            The IRQ handler function must be provided as the mandatory irq_handler
            driver operation. It will get passed directly to
            <function>request_irq</function> and thus has the same prototype as all
            IRQ handlers. It will get called with a pointer to the DRM device as the
            second argument.
          </para>
          <para>
            Finally the function calls the optional
            <methodname>irq_postinstall</methodname> driver operation. The operation
            usually enables interrupts (excluding the vblank interrupt, which is
            enabled separately), but drivers may choose to enable/disable interrupts
            at a different time.
          </para>
          <para>
            <function>drm_irq_uninstall</function> is similarly used to uninstall an
            IRQ handler. It starts by waking up all processes waiting on a vblank
            interrupt to make sure they don't hang, and then calls the optional
            <methodname>irq_uninstall</methodname> driver operation. The operation
            must disable all hardware interrupts. Finally the function frees the IRQ
            by calling <function>free_irq</function>.
          </para>
        </sect4>
        <sect4>
          <title>Manual IRQ Registration</title>
          <para>
            Drivers that require multiple interrupt handlers can't use the managed
            IRQ registration functions. In that case IRQs must be registered and
            unregistered manually (usually with the <function>request_irq</function>
            and <function>free_irq</function> functions, or their devm_* equivalent).
          </para>
          <para>
            When manually registering IRQs, drivers must not set the DRIVER_HAVE_IRQ
            driver feature flag, and must not provide the
	    <methodname>irq_handler</methodname> driver operation. They must set the
	    <structname>drm_device</structname> <structfield>irq_enabled</structfield>
	    field to 1 upon registration of the IRQs, and clear it to 0 after
	    unregistering the IRQs.
          </para>
        </sect4>
      </sect3>
      <sect3>
        <title>Memory Manager Initialization</title>
        <para>
          Every DRM driver requires a memory manager which must be initialized at
          load time. DRM currently contains two memory managers, the Translation
          Table Manager (TTM) and the Graphics Execution Manager (GEM).
          This document describes the use of the GEM memory manager only. See
          <xref linkend="drm-memory-management"/> for details.
        </para>
      </sect3>
      <sect3>
        <title>Miscellaneous Device Configuration</title>
        <para>
          Another task that may be necessary for PCI devices during configuration
          is mapping the video BIOS. On many devices, the VBIOS describes device
          configuration, LCD panel timings (if any), and contains flags indicating
          device state. Mapping the BIOS can be done using the pci_map_rom() call,
          a convenience function that takes care of mapping the actual ROM,
          whether it has been shadowed into memory (typically at address 0xc0000)
          or exists on the PCI device in the ROM BAR. Note that after the ROM has
          been mapped and any necessary information has been extracted, it should
          be unmapped; on many devices, the ROM address decoder is shared with
          other BARs, so leaving it mapped could cause undesired behaviour like
          hangs or memory corruption.
  <!--!Fdrivers/pci/rom.c pci_map_rom-->
        </para>
      </sect3>
    </sect2>
  </sect1>

  <!-- Internals: memory management -->

  <sect1 id="drm-memory-management">
    <title>Memory management</title>
    <para>
      Modern Linux systems require large amount of graphics memory to store
      frame buffers, textures, vertices and other graphics-related data. Given
      the very dynamic nature of many of that data, managing graphics memory
      efficiently is thus crucial for the graphics stack and plays a central
      role in the DRM infrastructure.
    </para>
    <para>
      The DRM core includes two memory managers, namely Translation Table Maps
      (TTM) and Graphics Execution Manager (GEM). TTM was the first DRM memory
      manager to be developed and tried to be a one-size-fits-them all
      solution. It provides a single userspace API to accommodate the need of
      all hardware, supporting both Unified Memory Architecture (UMA) devices
      and devices with dedicated video RAM (i.e. most discrete video cards).
      This resulted in a large, complex piece of code that turned out to be
      hard to use for driver development.
    </para>
    <para>
      GEM started as an Intel-sponsored project in reaction to TTM's
      complexity. Its design philosophy is completely different: instead of
      providing a solution to every graphics memory-related problems, GEM
      identified common code between drivers and created a support library to
      share it. GEM has simpler initialization and execution requirements than
      TTM, but has no video RAM management capabilities and is thus limited to
      UMA devices.
    </para>
    <sect2>
      <title>The Translation Table Manager (TTM)</title>
      <para>
	TTM design background and information belongs here.
      </para>
      <sect3>
	<title>TTM initialization</title>
        <warning><para>This section is outdated.</para></warning>
        <para>
          Drivers wishing to support TTM must fill out a drm_bo_driver
          structure. The structure contains several fields with function
          pointers for initializing the TTM, allocating and freeing memory,
          waiting for command completion and fence synchronization, and memory
          migration. See the radeon_ttm.c file for an example of usage.
	</para>
	<para>
	  The ttm_global_reference structure is made up of several fields:
	</para>
	<programlisting>
	  struct ttm_global_reference {
	  	enum ttm_global_types global_type;
	  	size_t size;
	  	void *object;
	  	int (*init) (struct ttm_global_reference *);
	  	void (*release) (struct ttm_global_reference *);
	  };
	</programlisting>
	<para>
	  There should be one global reference structure for your memory
	  manager as a whole, and there will be others for each object
	  created by the memory manager at runtime.  Your global TTM should
	  have a type of TTM_GLOBAL_TTM_MEM.  The size field for the global
	  object should be sizeof(struct ttm_mem_global), and the init and
	  release hooks should point at your driver-specific init and
	  release routines, which probably eventually call
	  ttm_mem_global_init and ttm_mem_global_release, respectively.
	</para>
	<para>
	  Once your global TTM accounting structure is set up and initialized
	  by calling ttm_global_item_ref() on it,
	  you need to create a buffer object TTM to
	  provide a pool for buffer object allocation by clients and the
	  kernel itself.  The type of this object should be TTM_GLOBAL_TTM_BO,
	  and its size should be sizeof(struct ttm_bo_global).  Again,
	  driver-specific init and release functions may be provided,
	  likely eventually calling ttm_bo_global_init() and
	  ttm_bo_global_release(), respectively.  Also, like the previous
	  object, ttm_global_item_ref() is used to create an initial reference
	  count for the TTM, which will call your initialization function.
	</para>
      </sect3>
    </sect2>
    <sect2 id="drm-gem">
      <title>The Graphics Execution Manager (GEM)</title>
      <para>
        The GEM design approach has resulted in a memory manager that doesn't
        provide full coverage of all (or even all common) use cases in its
        userspace or kernel API. GEM exposes a set of standard memory-related
        operations to userspace and a set of helper functions to drivers, and let
        drivers implement hardware-specific operations with their own private API.
      </para>
      <para>
        The GEM userspace API is described in the
        <ulink url="http://lwn.net/Articles/283798/"><citetitle>GEM - the Graphics
        Execution Manager</citetitle></ulink> article on LWN. While slightly
        outdated, the document provides a good overview of the GEM API principles.
        Buffer allocation and read and write operations, described as part of the
        common GEM API, are currently implemented using driver-specific ioctls.
      </para>
      <para>
        GEM is data-agnostic. It manages abstract buffer objects without knowing
        what individual buffers contain. APIs that require knowledge of buffer
        contents or purpose, such as buffer allocation or synchronization
        primitives, are thus outside of the scope of GEM and must be implemented
        using driver-specific ioctls.
      </para>
      <para>
	On a fundamental level, GEM involves several operations:
	<itemizedlist>
	  <listitem>Memory allocation and freeing</listitem>
	  <listitem>Command execution</listitem>
	  <listitem>Aperture management at command execution time</listitem>
	</itemizedlist>
	Buffer object allocation is relatively straightforward and largely
        provided by Linux's shmem layer, which provides memory to back each
        object.
      </para>
      <para>
        Device-specific operations, such as command execution, pinning, buffer
	read &amp; write, mapping, and domain ownership transfers are left to
        driver-specific ioctls.
      </para>
      <sect3>
        <title>GEM Initialization</title>
        <para>
          Drivers that use GEM must set the DRIVER_GEM bit in the struct
          <structname>drm_driver</structname>
          <structfield>driver_features</structfield> field. The DRM core will
          then automatically initialize the GEM core before calling the
          <methodname>load</methodname> operation. Behind the scene, this will
          create a DRM Memory Manager object which provides an address space
          pool for object allocation.
        </para>
        <para>
          In a KMS configuration, drivers need to allocate and initialize a
          command ring buffer following core GEM initialization if required by
          the hardware. UMA devices usually have what is called a "stolen"
          memory region, which provides space for the initial framebuffer and
          large, contiguous memory regions required by the device. This space is
          typically not managed by GEM, and must be initialized separately into
          its own DRM MM object.
        </para>
      </sect3>
      <sect3>
        <title>GEM Objects Creation</title>
        <para>
          GEM splits creation of GEM objects and allocation of the memory that
          backs them in two distinct operations.
        </para>
        <para>
          GEM objects are represented by an instance of struct
          <structname>drm_gem_object</structname>. Drivers usually need to extend
          GEM objects with private information and thus create a driver-specific
          GEM object structure type that embeds an instance of struct
          <structname>drm_gem_object</structname>.
        </para>
        <para>
          To create a GEM object, a driver allocates memory for an instance of its
          specific GEM object type and initializes the embedded struct
          <structname>drm_gem_object</structname> with a call to
          <function>drm_gem_object_init</function>. The function takes a pointer to
          the DRM device, a pointer to the GEM object and the buffer object size
          in bytes.
        </para>
        <para>
          GEM uses shmem to allocate anonymous pageable memory.
          <function>drm_gem_object_init</function> will create an shmfs file of
          the requested size and store it into the struct
          <structname>drm_gem_object</structname> <structfield>filp</structfield>
          field. The memory is used as either main storage for the object when the
          graphics hardware uses system memory directly or as a backing store
          otherwise.
        </para>
        <para>
          Drivers are responsible for the actual physical pages allocation by
          calling <function>shmem_read_mapping_page_gfp</function> for each page.
          Note that they can decide to allocate pages when initializing the GEM
          object, or to delay allocation until the memory is needed (for instance
          when a page fault occurs as a result of a userspace memory access or
          when the driver needs to start a DMA transfer involving the memory).
        </para>
        <para>
          Anonymous pageable memory allocation is not always desired, for instance
          when the hardware requires physically contiguous system memory as is
          often the case in embedded devices. Drivers can create GEM objects with
          no shmfs backing (called private GEM objects) by initializing them with
          a call to <function>drm_gem_private_object_init</function> instead of
          <function>drm_gem_object_init</function>. Storage for private GEM
          objects must be managed by drivers.
        </para>
        <para>
          Drivers that do not need to extend GEM objects with private information
          can call the <function>drm_gem_object_alloc</function> function to
          allocate and initialize a struct <structname>drm_gem_object</structname>
          instance. The GEM core will call the optional driver
          <methodname>gem_init_object</methodname> operation after initializing
          the GEM object with <function>drm_gem_object_init</function>.
          <synopsis>int (*gem_init_object) (struct drm_gem_object *obj);</synopsis>
        </para>
        <para>
          No alloc-and-init function exists for private GEM objects.
        </para>
      </sect3>
      <sect3>
        <title>GEM Objects Lifetime</title>
        <para>
          All GEM objects are reference-counted by the GEM core. References can be
          acquired and release by <function>calling drm_gem_object_reference</function>
          and <function>drm_gem_object_unreference</function> respectively. The
          caller must hold the <structname>drm_device</structname>
          <structfield>struct_mutex</structfield> lock. As a convenience, GEM
          provides the <function>drm_gem_object_reference_unlocked</function> and
          <function>drm_gem_object_unreference_unlocked</function> functions that
          can be called without holding the lock.
        </para>
        <para>
          When the last reference to a GEM object is released the GEM core calls
          the <structname>drm_driver</structname>
          <methodname>gem_free_object</methodname> operation. That operation is
          mandatory for GEM-enabled drivers and must free the GEM object and all
          associated resources.
        </para>
        <para>
          <synopsis>void (*gem_free_object) (struct drm_gem_object *obj);</synopsis>
          Drivers are responsible for freeing all GEM object resources, including
          the resources created by the GEM core. If an mmap offset has been
          created for the object (in which case
          <structname>drm_gem_object</structname>::<structfield>map_list</structfield>::<structfield>map</structfield>
          is not NULL) it must be freed by a call to
          <function>drm_gem_free_mmap_offset</function>. The shmfs backing store
          must be released by calling <function>drm_gem_object_release</function>
          (that function can safely be called if no shmfs backing store has been
          created).
        </para>
      </sect3>
      <sect3>
        <title>GEM Objects Naming</title>
        <para>
          Communication between userspace and the kernel refers to GEM objects
          using local handles, global names or, more recently, file descriptors.
          All of those are 32-bit integer values; the usual Linux kernel limits
          apply to the file descriptors.
        </para>
        <para>
          GEM handles are local to a DRM file. Applications get a handle to a GEM
          object through a driver-specific ioctl, and can use that handle to refer
          to the GEM object in other standard or driver-specific ioctls. Closing a
          DRM file handle frees all its GEM handles and dereferences the
          associated GEM objects.
        </para>
        <para>
          To create a handle for a GEM object drivers call
          <function>drm_gem_handle_create</function>. The function takes a pointer
          to the DRM file and the GEM object and returns a locally unique handle.
          When the handle is no longer needed drivers delete it with a call to
          <function>drm_gem_handle_delete</function>. Finally the GEM object
          associated with a handle can be retrieved by a call to
          <function>drm_gem_object_lookup</function>.
        </para>
        <para>
          Handles don't take ownership of GEM objects, they only take a reference
          to the object that will be dropped when the handle is destroyed. To
          avoid leaking GEM objects, drivers must make sure they drop the
          reference(s) they own (such as the initial reference taken at object
          creation time) as appropriate, without any special consideration for the
          handle. For example, in the particular case of combined GEM object and
          handle creation in the implementation of the
          <methodname>dumb_create</methodname> operation, drivers must drop the
          initial reference to the GEM object before returning the handle.
        </para>
        <para>
          GEM names are similar in purpose to handles but are not local to DRM
          files. They can be passed between processes to reference a GEM object
          globally. Names can't be used directly to refer to objects in the DRM
          API, applications must convert handles to names and names to handles
          using the DRM_IOCTL_GEM_FLINK and DRM_IOCTL_GEM_OPEN ioctls
          respectively. The conversion is handled by the DRM core without any
          driver-specific support.
        </para>
	<para>
	  GEM also supports buffer sharing with dma-buf file descriptors through
	  PRIME. GEM-based drivers must use the provided helpers functions to
	  implement the exporting and importing correctly. See <xref linkend="drm-prime-support" />.
	  Since sharing file descriptors is inherently more secure than the
	  easily guessable and global GEM names it is the preferred buffer
	  sharing mechanism. Sharing buffers through GEM names is only supported
	  for legacy userspace. Furthermore PRIME also allows cross-device
	  buffer sharing since it is based on dma-bufs.
	</para>
      </sect3>
      <sect3 id="drm-gem-objects-mapping">
        <title>GEM Objects Mapping</title>
        <para>
          Because mapping operations are fairly heavyweight GEM favours
          read/write-like access to buffers, implemented through driver-specific
          ioctls, over mapping buffers to userspace. However, when random access
          to the buffer is needed (to perform software rendering for instance),
          direct access to the object can be more efficient.
        </para>
        <para>
          The mmap system call can't be used directly to map GEM objects, as they
          don't have their own file handle. Two alternative methods currently
          co-exist to map GEM objects to userspace. The first method uses a
          driver-specific ioctl to perform the mapping operation, calling
          <function>do_mmap</function> under the hood. This is often considered
          dubious, seems to be discouraged for new GEM-enabled drivers, and will
          thus not be described here.
        </para>
        <para>
          The second method uses the mmap system call on the DRM file handle.
          <synopsis>void *mmap(void *addr, size_t length, int prot, int flags, int fd,
             off_t offset);</synopsis>
          DRM identifies the GEM object to be mapped by a fake offset passed
          through the mmap offset argument. Prior to being mapped, a GEM object
          must thus be associated with a fake offset. To do so, drivers must call
          <function>drm_gem_create_mmap_offset</function> on the object. The
          function allocates a fake offset range from a pool and stores the
          offset divided by PAGE_SIZE in
          <literal>obj-&gt;map_list.hash.key</literal>. Care must be taken not to
          call <function>drm_gem_create_mmap_offset</function> if a fake offset
          has already been allocated for the object. This can be tested by
          <literal>obj-&gt;map_list.map</literal> being non-NULL.
        </para>
        <para>
          Once allocated, the fake offset value
          (<literal>obj-&gt;map_list.hash.key &lt;&lt; PAGE_SHIFT</literal>)
          must be passed to the application in a driver-specific way and can then
          be used as the mmap offset argument.
        </para>
        <para>
          The GEM core provides a helper method <function>drm_gem_mmap</function>
          to handle object mapping. The method can be set directly as the mmap
          file operation handler. It will look up the GEM object based on the
          offset value and set the VMA operations to the
          <structname>drm_driver</structname> <structfield>gem_vm_ops</structfield>
          field. Note that <function>drm_gem_mmap</function> doesn't map memory to
          userspace, but relies on the driver-provided fault handler to map pages
          individually.
        </para>
        <para>
          To use <function>drm_gem_mmap</function>, drivers must fill the struct
          <structname>drm_driver</structname> <structfield>gem_vm_ops</structfield>
          field with a pointer to VM operations.
        </para>
        <para>
          <synopsis>struct vm_operations_struct *gem_vm_ops

  struct vm_operations_struct {
          void (*open)(struct vm_area_struct * area);
          void (*close)(struct vm_area_struct * area);
          int (*fault)(struct vm_area_struct *vma, struct vm_fault *vmf);
  };</synopsis>
        </para>
        <para>
          The <methodname>open</methodname> and <methodname>close</methodname>
          operations must update the GEM object reference count. Drivers can use
          the <function>drm_gem_vm_open</function> and
          <function>drm_gem_vm_close</function> helper functions directly as open
          and close handlers.
        </para>
        <para>
          The fault operation handler is responsible for mapping individual pages
          to userspace when a page fault occurs. Depending on the memory
          allocation scheme, drivers can allocate pages at fault time, or can
          decide to allocate memory for the GEM object at the time the object is
          created.
        </para>
        <para>
          Drivers that want to map the GEM object upfront instead of handling page
          faults can implement their own mmap file operation handler.
        </para>
      </sect3>
      <sect3>
        <title>Memory Coherency</title>
        <para>
          When mapped to the device or used in a command buffer, backing pages
          for an object are flushed to memory and marked write combined so as to
          be coherent with the GPU. Likewise, if the CPU accesses an object
          after the GPU has finished rendering to the object, then the object
          must be made coherent with the CPU's view of memory, usually involving
          GPU cache flushing of various kinds. This core CPU&lt;-&gt;GPU
          coherency management is provided by a device-specific ioctl, which
          evaluates an object's current domain and performs any necessary
          flushing or synchronization to put the object into the desired
          coherency domain (note that the object may be busy, i.e. an active
          render target; in that case, setting the domain blocks the client and
          waits for rendering to complete before performing any necessary
          flushing operations).
        </para>
      </sect3>
      <sect3>
        <title>Command Execution</title>
        <para>
	  Perhaps the most important GEM function for GPU devices is providing a
          command execution interface to clients. Client programs construct
          command buffers containing references to previously allocated memory
          objects, and then submit them to GEM. At that point, GEM takes care to
          bind all the objects into the GTT, execute the buffer, and provide
          necessary synchronization between clients accessing the same buffers.
          This often involves evicting some objects from the GTT and re-binding
          others (a fairly expensive operation), and providing relocation
          support which hides fixed GTT offsets from clients. Clients must take
          care not to submit command buffers that reference more objects than
          can fit in the GTT; otherwise, GEM will reject them and no rendering
          will occur. Similarly, if several objects in the buffer require fence
          registers to be allocated for correct rendering (e.g. 2D blits on
          pre-965 chips), care must be taken not to require more fence registers
          than are available to the client. Such resource management should be
          abstracted from the client in libdrm.
        </para>
      </sect3>
      <sect3>
        <title>GEM Function Reference</title>
!Edrivers/gpu/drm/drm_gem.c
      </sect3>
      </sect2>
      <sect2>
	<title>VMA Offset Manager</title>
!Pdrivers/gpu/drm/drm_vma_manager.c vma offset manager
!Edrivers/gpu/drm/drm_vma_manager.c
!Iinclude/drm/drm_vma_manager.h
      </sect2>
      <sect2 id="drm-prime-support">
	<title>PRIME Buffer Sharing</title>
	<para>
	  PRIME is the cross device buffer sharing framework in drm, originally
	  created for the OPTIMUS range of multi-gpu platforms. To userspace
	  PRIME buffers are dma-buf based file descriptors.
	</para>
	<sect3>
	  <title>Overview and Driver Interface</title>
	  <para>
	    Similar to GEM global names, PRIME file descriptors are
	    also used to share buffer objects across processes. They offer
	    additional security: as file descriptors must be explicitly sent over
	    UNIX domain sockets to be shared between applications, they can't be
	    guessed like the globally unique GEM names.
	  </para>
	  <para>
	    Drivers that support the PRIME
	    API must set the DRIVER_PRIME bit in the struct
	    <structname>drm_driver</structname>
	    <structfield>driver_features</structfield> field, and implement the
	    <methodname>prime_handle_to_fd</methodname> and
	    <methodname>prime_fd_to_handle</methodname> operations.
	  </para>
	  <para>
	    <synopsis>int (*prime_handle_to_fd)(struct drm_device *dev,
			  struct drm_file *file_priv, uint32_t handle,
			  uint32_t flags, int *prime_fd);
int (*prime_fd_to_handle)(struct drm_device *dev,
			  struct drm_file *file_priv, int prime_fd,
			  uint32_t *handle);</synopsis>
	    Those two operations convert a handle to a PRIME file descriptor and
	    vice versa. Drivers must use the kernel dma-buf buffer sharing framework
	    to manage the PRIME file descriptors. Similar to the mode setting
	    API PRIME is agnostic to the underlying buffer object manager, as
	    long as handles are 32bit unsigned integers.
	  </para>
	  <para>
	    While non-GEM drivers must implement the operations themselves, GEM
	    drivers must use the <function>drm_gem_prime_handle_to_fd</function>
	    and <function>drm_gem_prime_fd_to_handle</function> helper functions.
	    Those helpers rely on the driver
	    <methodname>gem_prime_export</methodname> and
	    <methodname>gem_prime_import</methodname> operations to create a dma-buf
	    instance from a GEM object (dma-buf exporter role) and to create a GEM
	    object from a dma-buf instance (dma-buf importer role).
	  </para>
	  <para>
	    <synopsis>struct dma_buf * (*gem_prime_export)(struct drm_device *dev,
				     struct drm_gem_object *obj,
				     int flags);
struct drm_gem_object * (*gem_prime_import)(struct drm_device *dev,
					    struct dma_buf *dma_buf);</synopsis>
	    These two operations are mandatory for GEM drivers that support
	    PRIME.
	  </para>
	</sect3>
        <sect3>
          <title>PRIME Helper Functions</title>
!Pdrivers/gpu/drm/drm_prime.c PRIME Helpers
        </sect3>
      </sect2>
      <sect2>
	<title>PRIME Function References</title>
!Edrivers/gpu/drm/drm_prime.c
      </sect2>
      <sect2>
	<title>DRM MM Range Allocator</title>
	<sect3>
	  <title>Overview</title>
!Pdrivers/gpu/drm/drm_mm.c Overview
	</sect3>
	<sect3>
	  <title>LRU Scan/Eviction Support</title>
!Pdrivers/gpu/drm/drm_mm.c lru scan roaster
	</sect3>
      </sect2>
      <sect2>
	<title>DRM MM Range Allocator Function References</title>
!Edrivers/gpu/drm/drm_mm.c
!Iinclude/drm/drm_mm.h
      </sect2>
  </sect1>

  <!-- Internals: mode setting -->

  <sect1 id="drm-mode-setting">
    <title>Mode Setting</title>
    <para>
      Drivers must initialize the mode setting core by calling
      <function>drm_mode_config_init</function> on the DRM device. The function
      initializes the <structname>drm_device</structname>
      <structfield>mode_config</structfield> field and never fails. Once done,
      mode configuration must be setup by initializing the following fields.
    </para>
    <itemizedlist>
      <listitem>
        <synopsis>int min_width, min_height;
int max_width, max_height;</synopsis>
        <para>
	  Minimum and maximum width and height of the frame buffers in pixel
	  units.
	</para>
      </listitem>
      <listitem>
        <synopsis>struct drm_mode_config_funcs *funcs;</synopsis>
	<para>Mode setting functions.</para>
      </listitem>
    </itemizedlist>
    <sect2>
      <title>Display Modes Function Reference</title>
!Iinclude/drm/drm_modes.h
!Edrivers/gpu/drm/drm_modes.c
    </sect2>
    <sect2>
      <title>Frame Buffer Creation</title>
      <synopsis>struct drm_framebuffer *(*fb_create)(struct drm_device *dev,
				     struct drm_file *file_priv,
				     struct drm_mode_fb_cmd2 *mode_cmd);</synopsis>
      <para>
        Frame buffers are abstract memory objects that provide a source of
        pixels to scanout to a CRTC. Applications explicitly request the
        creation of frame buffers through the DRM_IOCTL_MODE_ADDFB(2) ioctls and
        receive an opaque handle that can be passed to the KMS CRTC control,
        plane configuration and page flip functions.
      </para>
      <para>
        Frame buffers rely on the underneath memory manager for low-level memory
        operations. When creating a frame buffer applications pass a memory
        handle (or a list of memory handles for multi-planar formats) through
	the <parameter>drm_mode_fb_cmd2</parameter> argument. For drivers using
	GEM as their userspace buffer management interface this would be a GEM
	handle.  Drivers are however free to use their own backing storage object
	handles, e.g. vmwgfx directly exposes special TTM handles to userspace
	and so expects TTM handles in the create ioctl and not GEM handles.
      </para>
      <para>
        Drivers must first validate the requested frame buffer parameters passed
        through the mode_cmd argument. In particular this is where invalid
        sizes, pixel formats or pitches can be caught.
      </para>
      <para>
        If the parameters are deemed valid, drivers then create, initialize and
        return an instance of struct <structname>drm_framebuffer</structname>.
        If desired the instance can be embedded in a larger driver-specific
	structure. Drivers must fill its <structfield>width</structfield>,
	<structfield>height</structfield>, <structfield>pitches</structfield>,
        <structfield>offsets</structfield>, <structfield>depth</structfield>,
        <structfield>bits_per_pixel</structfield> and
        <structfield>pixel_format</structfield> fields from the values passed
        through the <parameter>drm_mode_fb_cmd2</parameter> argument. They
        should call the <function>drm_helper_mode_fill_fb_struct</function>
        helper function to do so.
      </para>

      <para>
	The initialization of the new framebuffer instance is finalized with a
	call to <function>drm_framebuffer_init</function> which takes a pointer
	to DRM frame buffer operations (struct
	<structname>drm_framebuffer_funcs</structname>). Note that this function
	publishes the framebuffer and so from this point on it can be accessed
	concurrently from other threads. Hence it must be the last step in the
	driver's framebuffer initialization sequence. Frame buffer operations
	are
        <itemizedlist>
          <listitem>
            <synopsis>int (*create_handle)(struct drm_framebuffer *fb,
		     struct drm_file *file_priv, unsigned int *handle);</synopsis>
            <para>
              Create a handle to the frame buffer underlying memory object. If
              the frame buffer uses a multi-plane format, the handle will
              reference the memory object associated with the first plane.
            </para>
            <para>
              Drivers call <function>drm_gem_handle_create</function> to create
              the handle.
            </para>
          </listitem>
          <listitem>
            <synopsis>void (*destroy)(struct drm_framebuffer *framebuffer);</synopsis>
            <para>
              Destroy the frame buffer object and frees all associated
              resources. Drivers must call
              <function>drm_framebuffer_cleanup</function> to free resources
              allocated by the DRM core for the frame buffer object, and must
              make sure to unreference all memory objects associated with the
              frame buffer. Handles created by the
              <methodname>create_handle</methodname> operation are released by
              the DRM core.
            </para>
          </listitem>
          <listitem>
            <synopsis>int (*dirty)(struct drm_framebuffer *framebuffer,
	     struct drm_file *file_priv, unsigned flags, unsigned color,
	     struct drm_clip_rect *clips, unsigned num_clips);</synopsis>
            <para>
              This optional operation notifies the driver that a region of the
              frame buffer has changed in response to a DRM_IOCTL_MODE_DIRTYFB
              ioctl call.
            </para>
          </listitem>
        </itemizedlist>
      </para>
      <para>
	The lifetime of a drm framebuffer is controlled with a reference count,
	drivers can grab additional references with
	<function>drm_framebuffer_reference</function>and drop them
	again with <function>drm_framebuffer_unreference</function>. For
	driver-private framebuffers for which the last reference is never
	dropped (e.g. for the fbdev framebuffer when the struct
	<structname>drm_framebuffer</structname> is embedded into the fbdev
	helper struct) drivers can manually clean up a framebuffer at module
	unload time with
	<function>drm_framebuffer_unregister_private</function>.
      </para>
    </sect2>
    <sect2>
      <title>Dumb Buffer Objects</title>
      <para>
	The KMS API doesn't standardize backing storage object creation and
	leaves it to driver-specific ioctls. Furthermore actually creating a
	buffer object even for GEM-based drivers is done through a
	driver-specific ioctl - GEM only has a common userspace interface for
	sharing and destroying objects. While not an issue for full-fledged
	graphics stacks that include device-specific userspace components (in
	libdrm for instance), this limit makes DRM-based early boot graphics
	unnecessarily complex.
      </para>
      <para>
        Dumb objects partly alleviate the problem by providing a standard
        API to create dumb buffers suitable for scanout, which can then be used
        to create KMS frame buffers.
      </para>
      <para>
        To support dumb objects drivers must implement the
        <methodname>dumb_create</methodname>,
        <methodname>dumb_destroy</methodname> and
        <methodname>dumb_map_offset</methodname> operations.
      </para>
      <itemizedlist>
        <listitem>
          <synopsis>int (*dumb_create)(struct drm_file *file_priv, struct drm_device *dev,
                   struct drm_mode_create_dumb *args);</synopsis>
          <para>
            The <methodname>dumb_create</methodname> operation creates a driver
	    object (GEM or TTM handle) suitable for scanout based on the
	    width, height and depth from the struct
	    <structname>drm_mode_create_dumb</structname> argument. It fills the
	    argument's <structfield>handle</structfield>,
	    <structfield>pitch</structfield> and <structfield>size</structfield>
	    fields with a handle for the newly created object and its line
            pitch and size in bytes.
          </para>
        </listitem>
        <listitem>
          <synopsis>int (*dumb_destroy)(struct drm_file *file_priv, struct drm_device *dev,
                    uint32_t handle);</synopsis>
          <para>
            The <methodname>dumb_destroy</methodname> operation destroys a dumb
            object created by <methodname>dumb_create</methodname>.
          </para>
        </listitem>
        <listitem>
          <synopsis>int (*dumb_map_offset)(struct drm_file *file_priv, struct drm_device *dev,
                       uint32_t handle, uint64_t *offset);</synopsis>
          <para>
            The <methodname>dumb_map_offset</methodname> operation associates an
            mmap fake offset with the object given by the handle and returns
            it. Drivers must use the
            <function>drm_gem_create_mmap_offset</function> function to
            associate the fake offset as described in
            <xref linkend="drm-gem-objects-mapping"/>.
          </para>
        </listitem>
      </itemizedlist>
      <para>
        Note that dumb objects may not be used for gpu acceleration, as has been
	attempted on some ARM embedded platforms. Such drivers really must have
	a hardware-specific ioctl to allocate suitable buffer objects.
      </para>
    </sect2>
    <sect2>
      <title>Output Polling</title>
      <synopsis>void (*output_poll_changed)(struct drm_device *dev);</synopsis>
      <para>
        This operation notifies the driver that the status of one or more
        connectors has changed. Drivers that use the fb helper can just call the
        <function>drm_fb_helper_hotplug_event</function> function to handle this
        operation.
      </para>
    </sect2>
    <sect2>
      <title>Locking</title>
      <para>
        Beside some lookup structures with their own locking (which is hidden
	behind the interface functions) most of the modeset state is protected
	by the <code>dev-&lt;mode_config.lock</code> mutex and additionally
	per-crtc locks to allow cursor updates, pageflips and similar operations
	to occur concurrently with background tasks like output detection.
	Operations which cross domains like a full modeset always grab all
	locks. Drivers there need to protect resources shared between crtcs with
	additional locking. They also need to be careful to always grab the
	relevant crtc locks if a modset functions touches crtc state, e.g. for
	load detection (which does only grab the <code>mode_config.lock</code>
	to allow concurrent screen updates on live crtcs).
      </para>
    </sect2>
  </sect1>

  <!-- Internals: kms initialization and cleanup -->

  <sect1 id="drm-kms-init">
    <title>KMS Initialization and Cleanup</title>
    <para>
      A KMS device is abstracted and exposed as a set of planes, CRTCs, encoders
      and connectors. KMS drivers must thus create and initialize all those
      objects at load time after initializing mode setting.
    </para>
    <sect2>
      <title>CRTCs (struct <structname>drm_crtc</structname>)</title>
      <para>
        A CRTC is an abstraction representing a part of the chip that contains a
	pointer to a scanout buffer. Therefore, the number of CRTCs available
	determines how many independent scanout buffers can be active at any
	given time. The CRTC structure contains several fields to support this:
	a pointer to some video memory (abstracted as a frame buffer object), a
	display mode, and an (x, y) offset into the video memory to support
	panning or configurations where one piece of video memory spans multiple
	CRTCs.
      </para>
      <sect3>
        <title>CRTC Initialization</title>
        <para>
          A KMS device must create and register at least one struct
          <structname>drm_crtc</structname> instance. The instance is allocated
          and zeroed by the driver, possibly as part of a larger structure, and
          registered with a call to <function>drm_crtc_init</function> with a
          pointer to CRTC functions.
        </para>
      </sect3>
      <sect3 id="drm-kms-crtcops">
        <title>CRTC Operations</title>
        <sect4>
          <title>Set Configuration</title>
          <synopsis>int (*set_config)(struct drm_mode_set *set);</synopsis>
          <para>
            Apply a new CRTC configuration to the device. The configuration
            specifies a CRTC, a frame buffer to scan out from, a (x,y) position in
            the frame buffer, a display mode and an array of connectors to drive
            with the CRTC if possible.
          </para>
          <para>
            If the frame buffer specified in the configuration is NULL, the driver
            must detach all encoders connected to the CRTC and all connectors
            attached to those encoders and disable them.
          </para>
          <para>
            This operation is called with the mode config lock held.
          </para>
          <note><para>
	    Note that the drm core has no notion of restoring the mode setting
	    state after resume, since all resume handling is in the full
	    responsibility of the driver. The common mode setting helper library
	    though provides a helper which can be used for this:
	    <function>drm_helper_resume_force_mode</function>.
          </para></note>
        </sect4>
        <sect4>
          <title>Page Flipping</title>
          <synopsis>int (*page_flip)(struct drm_crtc *crtc, struct drm_framebuffer *fb,
                   struct drm_pending_vblank_event *event);</synopsis>
          <para>
            Schedule a page flip to the given frame buffer for the CRTC. This
            operation is called with the mode config mutex held.
          </para>
          <para>
            Page flipping is a synchronization mechanism that replaces the frame
            buffer being scanned out by the CRTC with a new frame buffer during
            vertical blanking, avoiding tearing. When an application requests a page
            flip the DRM core verifies that the new frame buffer is large enough to
            be scanned out by  the CRTC in the currently configured mode and then
            calls the CRTC <methodname>page_flip</methodname> operation with a
            pointer to the new frame buffer.
          </para>
          <para>
            The <methodname>page_flip</methodname> operation schedules a page flip.
            Once any pending rendering targeting the new frame buffer has
            completed, the CRTC will be reprogrammed to display that frame buffer
            after the next vertical refresh. The operation must return immediately
            without waiting for rendering or page flip to complete and must block
            any new rendering to the frame buffer until the page flip completes.
          </para>
          <para>
            If a page flip can be successfully scheduled the driver must set the
            <code>drm_crtc-&lt;fb</code> field to the new framebuffer pointed to
            by <code>fb</code>. This is important so that the reference counting
            on framebuffers stays balanced.
          </para>
          <para>
            If a page flip is already pending, the
            <methodname>page_flip</methodname> operation must return
            -<errorname>EBUSY</errorname>.
          </para>
          <para>
            To synchronize page flip to vertical blanking the driver will likely
            need to enable vertical blanking interrupts. It should call
            <function>drm_vblank_get</function> for that purpose, and call
            <function>drm_vblank_put</function> after the page flip completes.
          </para>
          <para>
            If the application has requested to be notified when page flip completes
            the <methodname>page_flip</methodname> operation will be called with a
            non-NULL <parameter>event</parameter> argument pointing to a
            <structname>drm_pending_vblank_event</structname> instance. Upon page
            flip completion the driver must call <methodname>drm_send_vblank_event</methodname>
            to fill in the event and send to wake up any waiting processes.
            This can be performed with
            <programlisting><![CDATA[
            spin_lock_irqsave(&dev->event_lock, flags);
            ...
            drm_send_vblank_event(dev, pipe, event);
            spin_unlock_irqrestore(&dev->event_lock, flags);
            ]]></programlisting>
          </para>
          <note><para>
            FIXME: Could drivers that don't need to wait for rendering to complete
            just add the event to <literal>dev-&gt;vblank_event_list</literal> and
            let the DRM core handle everything, as for "normal" vertical blanking
            events?
          </para></note>
          <para>
            While waiting for the page flip to complete, the
            <literal>event-&gt;base.link</literal> list head can be used freely by
            the driver to store the pending event in a driver-specific list.
          </para>
          <para>
            If the file handle is closed before the event is signaled, drivers must
            take care to destroy the event in their
            <methodname>preclose</methodname> operation (and, if needed, call
            <function>drm_vblank_put</function>).
          </para>
        </sect4>
        <sect4>
          <title>Miscellaneous</title>
          <itemizedlist>
            <listitem>
              <synopsis>void (*set_property)(struct drm_crtc *crtc,
                     struct drm_property *property, uint64_t value);</synopsis>
              <para>
                Set the value of the given CRTC property to
                <parameter>value</parameter>. See <xref linkend="drm-kms-properties"/>
                for more information about properties.
              </para>
            </listitem>
            <listitem>
              <synopsis>void (*gamma_set)(struct drm_crtc *crtc, u16 *r, u16 *g, u16 *b,
                        uint32_t start, uint32_t size);</synopsis>
              <para>
                Apply a gamma table to the device. The operation is optional.
              </para>
            </listitem>
            <listitem>
              <synopsis>void (*destroy)(struct drm_crtc *crtc);</synopsis>
              <para>
                Destroy the CRTC when not needed anymore. See
                <xref linkend="drm-kms-init"/>.
              </para>
            </listitem>
          </itemizedlist>
        </sect4>
      </sect3>
    </sect2>
    <sect2>
      <title>Planes (struct <structname>drm_plane</structname>)</title>
      <para>
        A plane represents an image source that can be blended with or overlayed
	on top of a CRTC during the scanout process. Planes are associated with
	a frame buffer to crop a portion of the image memory (source) and
	optionally scale it to a destination size. The result is then blended
	with or overlayed on top of a CRTC.
      </para>
      <para>
      The DRM core recognizes three types of planes:
      <itemizedlist>
        <listitem>
        DRM_PLANE_TYPE_PRIMARY represents a "main" plane for a CRTC.  Primary
        planes are the planes operated upon by by CRTC modesetting and flipping
        operations described in <xref linkend="drm-kms-crtcops"/>.
        </listitem>
        <listitem>
        DRM_PLANE_TYPE_CURSOR represents a "cursor" plane for a CRTC.  Cursor
        planes are the planes operated upon by the DRM_IOCTL_MODE_CURSOR and
        DRM_IOCTL_MODE_CURSOR2 ioctls.
        </listitem>
        <listitem>
        DRM_PLANE_TYPE_OVERLAY represents all non-primary, non-cursor planes.
        Some drivers refer to these types of planes as "sprites" internally.
        </listitem>
      </itemizedlist>
      For compatibility with legacy userspace, only overlay planes are made
      available to userspace by default.  Userspace clients may set the
      DRM_CLIENT_CAP_UNIVERSAL_PLANES client capability bit to indicate that
      they wish to receive a universal plane list containing all plane types.
      </para>
      <sect3>
        <title>Plane Initialization</title>
        <para>
          To create a plane, a KMS drivers allocates and
          zeroes an instances of struct <structname>drm_plane</structname>
          (possibly as part of a larger structure) and registers it with a call
          to <function>drm_universal_plane_init</function>. The function takes a bitmask
          of the CRTCs that can be associated with the plane, a pointer to the
          plane functions, a list of format supported formats, and the type of
          plane (primary, cursor, or overlay) being initialized.
        </para>
        <para>
          Cursor and overlay planes are optional.  All drivers should provide
          one primary plane per CRTC (although this requirement may change in
          the future); drivers that do not wish to provide special handling for
          primary planes may make use of the helper functions described in
          <xref linkend="drm-kms-planehelpers"/> to create and register a
          primary plane with standard capabilities.
        </para>
      </sect3>
      <sect3>
        <title>Plane Operations</title>
        <itemizedlist>
          <listitem>
            <synopsis>int (*update_plane)(struct drm_plane *plane, struct drm_crtc *crtc,
                        struct drm_framebuffer *fb, int crtc_x, int crtc_y,
                        unsigned int crtc_w, unsigned int crtc_h,
                        uint32_t src_x, uint32_t src_y,
                        uint32_t src_w, uint32_t src_h);</synopsis>
            <para>
              Enable and configure the plane to use the given CRTC and frame buffer.
            </para>
            <para>
              The source rectangle in frame buffer memory coordinates is given by
              the <parameter>src_x</parameter>, <parameter>src_y</parameter>,
              <parameter>src_w</parameter> and <parameter>src_h</parameter>
              parameters (as 16.16 fixed point values). Devices that don't support
              subpixel plane coordinates can ignore the fractional part.
            </para>
            <para>
              The destination rectangle in CRTC coordinates is given by the
              <parameter>crtc_x</parameter>, <parameter>crtc_y</parameter>,
              <parameter>crtc_w</parameter> and <parameter>crtc_h</parameter>
              parameters (as integer values). Devices scale the source rectangle to
              the destination rectangle. If scaling is not supported, and the source
              rectangle size doesn't match the destination rectangle size, the
              driver must return a -<errorname>EINVAL</errorname> error.
            </para>
          </listitem>
          <listitem>
            <synopsis>int (*disable_plane)(struct drm_plane *plane);</synopsis>
            <para>
              Disable the plane. The DRM core calls this method in response to a
              DRM_IOCTL_MODE_SETPLANE ioctl call with the frame buffer ID set to 0.
              Disabled planes must not be processed by the CRTC.
            </para>
          </listitem>
          <listitem>
            <synopsis>void (*destroy)(struct drm_plane *plane);</synopsis>
            <para>
              Destroy the plane when not needed anymore. See
              <xref linkend="drm-kms-init"/>.
            </para>
          </listitem>
        </itemizedlist>
      </sect3>
    </sect2>
    <sect2>
      <title>Encoders (struct <structname>drm_encoder</structname>)</title>
      <para>
        An encoder takes pixel data from a CRTC and converts it to a format
	suitable for any attached connectors. On some devices, it may be
	possible to have a CRTC send data to more than one encoder. In that
	case, both encoders would receive data from the same scanout buffer,
	resulting in a "cloned" display configuration across the connectors
	attached to each encoder.
      </para>
      <sect3>
        <title>Encoder Initialization</title>
        <para>
          As for CRTCs, a KMS driver must create, initialize and register at
          least one struct <structname>drm_encoder</structname> instance. The
          instance is allocated and zeroed by the driver, possibly as part of a
          larger structure.
        </para>
        <para>
          Drivers must initialize the struct <structname>drm_encoder</structname>
          <structfield>possible_crtcs</structfield> and
          <structfield>possible_clones</structfield> fields before registering the
          encoder. Both fields are bitmasks of respectively the CRTCs that the
          encoder can be connected to, and sibling encoders candidate for cloning.
        </para>
        <para>
          After being initialized, the encoder must be registered with a call to
          <function>drm_encoder_init</function>. The function takes a pointer to
          the encoder functions and an encoder type. Supported types are
          <itemizedlist>
            <listitem>
              DRM_MODE_ENCODER_DAC for VGA and analog on DVI-I/DVI-A
              </listitem>
            <listitem>
              DRM_MODE_ENCODER_TMDS for DVI, HDMI and (embedded) DisplayPort
            </listitem>
            <listitem>
              DRM_MODE_ENCODER_LVDS for display panels
            </listitem>
            <listitem>
              DRM_MODE_ENCODER_TVDAC for TV output (Composite, S-Video, Component,
              SCART)
            </listitem>
            <listitem>
              DRM_MODE_ENCODER_VIRTUAL for virtual machine displays
            </listitem>
          </itemizedlist>
        </para>
        <para>
          Encoders must be attached to a CRTC to be used. DRM drivers leave
          encoders unattached at initialization time. Applications (or the fbdev
          compatibility layer when implemented) are responsible for attaching the
          encoders they want to use to a CRTC.
        </para>
      </sect3>
      <sect3>
        <title>Encoder Operations</title>
        <itemizedlist>
          <listitem>
            <synopsis>void (*destroy)(struct drm_encoder *encoder);</synopsis>
            <para>
              Called to destroy the encoder when not needed anymore. See
              <xref linkend="drm-kms-init"/>.
            </para>
          </listitem>
          <listitem>
            <synopsis>void (*set_property)(struct drm_plane *plane,
                     struct drm_property *property, uint64_t value);</synopsis>
            <para>
              Set the value of the given plane property to
              <parameter>value</parameter>. See <xref linkend="drm-kms-properties"/>
              for more information about properties.
            </para>
          </listitem>
        </itemizedlist>
      </sect3>
    </sect2>
    <sect2>
      <title>Connectors (struct <structname>drm_connector</structname>)</title>
      <para>
        A connector is the final destination for pixel data on a device, and
	usually connects directly to an external display device like a monitor
	or laptop panel. A connector can only be attached to one encoder at a
	time. The connector is also the structure where information about the
	attached display is kept, so it contains fields for display data, EDID
	data, DPMS &amp; connection status, and information about modes
	supported on the attached displays.
      </para>
      <sect3>
        <title>Connector Initialization</title>
        <para>
          Finally a KMS driver must create, initialize, register and attach at
          least one struct <structname>drm_connector</structname> instance. The
          instance is created as other KMS objects and initialized by setting the
          following fields.
        </para>
        <variablelist>
          <varlistentry>
            <term><structfield>interlace_allowed</structfield></term>
            <listitem><para>
              Whether the connector can handle interlaced modes.
            </para></listitem>
          </varlistentry>
          <varlistentry>
            <term><structfield>doublescan_allowed</structfield></term>
            <listitem><para>
              Whether the connector can handle doublescan.
            </para></listitem>
          </varlistentry>
          <varlistentry>
            <term><structfield>display_info
            </structfield></term>
            <listitem><para>
              Display information is filled from EDID information when a display
              is detected. For non hot-pluggable displays such as flat panels in
              embedded systems, the driver should initialize the
              <structfield>display_info</structfield>.<structfield>width_mm</structfield>
              and
              <structfield>display_info</structfield>.<structfield>height_mm</structfield>
              fields with the physical size of the display.
            </para></listitem>
          </varlistentry>
          <varlistentry>
            <term id="drm-kms-connector-polled"><structfield>polled</structfield></term>
            <listitem><para>
              Connector polling mode, a combination of
              <variablelist>
                <varlistentry>
                  <term>DRM_CONNECTOR_POLL_HPD</term>
                  <listitem><para>
                    The connector generates hotplug events and doesn't need to be
                    periodically polled. The CONNECT and DISCONNECT flags must not
                    be set together with the HPD flag.
                  </para></listitem>
                </varlistentry>
                <varlistentry>
                  <term>DRM_CONNECTOR_POLL_CONNECT</term>
                  <listitem><para>
                    Periodically poll the connector for connection.
                  </para></listitem>
                </varlistentry>
                <varlistentry>
                  <term>DRM_CONNECTOR_POLL_DISCONNECT</term>
                  <listitem><para>
                    Periodically poll the connector for disconnection.
                  </para></listitem>
                </varlistentry>
              </variablelist>
              Set to 0 for connectors that don't support connection status
              discovery.
            </para></listitem>
          </varlistentry>
        </variablelist>
        <para>
          The connector is then registered with a call to
          <function>drm_connector_init</function> with a pointer to the connector
          functions and a connector type, and exposed through sysfs with a call to
          <function>drm_connector_register</function>.
        </para>
        <para>
          Supported connector types are
          <itemizedlist>
            <listitem>DRM_MODE_CONNECTOR_VGA</listitem>
            <listitem>DRM_MODE_CONNECTOR_DVII</listitem>
            <listitem>DRM_MODE_CONNECTOR_DVID</listitem>
            <listitem>DRM_MODE_CONNECTOR_DVIA</listitem>
            <listitem>DRM_MODE_CONNECTOR_Composite</listitem>
            <listitem>DRM_MODE_CONNECTOR_SVIDEO</listitem>
            <listitem>DRM_MODE_CONNECTOR_LVDS</listitem>
            <listitem>DRM_MODE_CONNECTOR_Component</listitem>
            <listitem>DRM_MODE_CONNECTOR_9PinDIN</listitem>
            <listitem>DRM_MODE_CONNECTOR_DisplayPort</listitem>
            <listitem>DRM_MODE_CONNECTOR_HDMIA</listitem>
            <listitem>DRM_MODE_CONNECTOR_HDMIB</listitem>
            <listitem>DRM_MODE_CONNECTOR_TV</listitem>
            <listitem>DRM_MODE_CONNECTOR_eDP</listitem>
            <listitem>DRM_MODE_CONNECTOR_VIRTUAL</listitem>
          </itemizedlist>
        </para>
        <para>
          Connectors must be attached to an encoder to be used. For devices that
          map connectors to encoders 1:1, the connector should be attached at
          initialization time with a call to
          <function>drm_mode_connector_attach_encoder</function>. The driver must
          also set the <structname>drm_connector</structname>
          <structfield>encoder</structfield> field to point to the attached
          encoder.
        </para>
        <para>
          Finally, drivers must initialize the connectors state change detection
          with a call to <function>drm_kms_helper_poll_init</function>. If at
          least one connector is pollable but can't generate hotplug interrupts
          (indicated by the DRM_CONNECTOR_POLL_CONNECT and
          DRM_CONNECTOR_POLL_DISCONNECT connector flags), a delayed work will
          automatically be queued to periodically poll for changes. Connectors
          that can generate hotplug interrupts must be marked with the
          DRM_CONNECTOR_POLL_HPD flag instead, and their interrupt handler must
          call <function>drm_helper_hpd_irq_event</function>. The function will
          queue a delayed work to check the state of all connectors, but no
          periodic polling will be done.
        </para>
      </sect3>
      <sect3>
        <title>Connector Operations</title>
        <note><para>
          Unless otherwise state, all operations are mandatory.
        </para></note>
        <sect4>
          <title>DPMS</title>
          <synopsis>void (*dpms)(struct drm_connector *connector, int mode);</synopsis>
          <para>
            The DPMS operation sets the power state of a connector. The mode
            argument is one of
            <itemizedlist>
              <listitem><para>DRM_MODE_DPMS_ON</para></listitem>
              <listitem><para>DRM_MODE_DPMS_STANDBY</para></listitem>
              <listitem><para>DRM_MODE_DPMS_SUSPEND</para></listitem>
              <listitem><para>DRM_MODE_DPMS_OFF</para></listitem>
            </itemizedlist>
          </para>
          <para>
            In all but DPMS_ON mode the encoder to which the connector is attached
            should put the display in low-power mode by driving its signals
            appropriately. If more than one connector is attached to the encoder
            care should be taken not to change the power state of other displays as
            a side effect. Low-power mode should be propagated to the encoders and
            CRTCs when all related connectors are put in low-power mode.
          </para>
        </sect4>
        <sect4>
          <title>Modes</title>
          <synopsis>int (*fill_modes)(struct drm_connector *connector, uint32_t max_width,
                      uint32_t max_height);</synopsis>
          <para>
            Fill the mode list with all supported modes for the connector. If the
            <parameter>max_width</parameter> and <parameter>max_height</parameter>
            arguments are non-zero, the implementation must ignore all modes wider
            than <parameter>max_width</parameter> or higher than
            <parameter>max_height</parameter>.
          </para>
          <para>
            The connector must also fill in this operation its
            <structfield>display_info</structfield>
            <structfield>width_mm</structfield> and
            <structfield>height_mm</structfield> fields with the connected display
            physical size in millimeters. The fields should be set to 0 if the value
            isn't known or is not applicable (for instance for projector devices).
          </para>
        </sect4>
        <sect4>
          <title>Connection Status</title>
          <para>
            The connection status is updated through polling or hotplug events when
            supported (see <xref linkend="drm-kms-connector-polled"/>). The status
            value is reported to userspace through ioctls and must not be used
            inside the driver, as it only gets initialized by a call to
            <function>drm_mode_getconnector</function> from userspace.
          </para>
          <synopsis>enum drm_connector_status (*detect)(struct drm_connector *connector,
                                        bool force);</synopsis>
          <para>
            Check to see if anything is attached to the connector. The
            <parameter>force</parameter> parameter is set to false whilst polling or
            to true when checking the connector due to user request.
            <parameter>force</parameter> can be used by the driver to avoid
            expensive, destructive operations during automated probing.
          </para>
          <para>
            Return connector_status_connected if something is connected to the
            connector, connector_status_disconnected if nothing is connected and
            connector_status_unknown if the connection state isn't known.
          </para>
          <para>
            Drivers should only return connector_status_connected if the connection
            status has really been probed as connected. Connectors that can't detect
            the connection status, or failed connection status probes, should return
            connector_status_unknown.
          </para>
        </sect4>
        <sect4>
          <title>Miscellaneous</title>
          <itemizedlist>
            <listitem>
              <synopsis>void (*set_property)(struct drm_connector *connector,
                     struct drm_property *property, uint64_t value);</synopsis>
              <para>
                Set the value of the given connector property to
                <parameter>value</parameter>. See <xref linkend="drm-kms-properties"/>
                for more information about properties.
              </para>
            </listitem>
            <listitem>
              <synopsis>void (*destroy)(struct drm_connector *connector);</synopsis>
              <para>
                Destroy the connector when not needed anymore. See
                <xref linkend="drm-kms-init"/>.
              </para>
            </listitem>
          </itemizedlist>
        </sect4>
      </sect3>
    </sect2>
    <sect2>
      <title>Cleanup</title>
      <para>
        The DRM core manages its objects' lifetime. When an object is not needed
	anymore the core calls its destroy function, which must clean up and
	free every resource allocated for the object. Every
	<function>drm_*_init</function> call must be matched with a
	corresponding <function>drm_*_cleanup</function> call to cleanup CRTCs
	(<function>drm_crtc_cleanup</function>), planes
	(<function>drm_plane_cleanup</function>), encoders
	(<function>drm_encoder_cleanup</function>) and connectors
	(<function>drm_connector_cleanup</function>). Furthermore, connectors
	that have been added to sysfs must be removed by a call to
	<function>drm_connector_unregister</function> before calling
	<function>drm_connector_cleanup</function>.
      </para>
      <para>
        Connectors state change detection must be cleanup up with a call to
	<function>drm_kms_helper_poll_fini</function>.
      </para>
    </sect2>
    <sect2>
      <title>Output discovery and initialization example</title>
      <programlisting><![CDATA[
void intel_crt_init(struct drm_device *dev)
{
	struct drm_connector *connector;
	struct intel_output *intel_output;

	intel_output = kzalloc(sizeof(struct intel_output), GFP_KERNEL);
	if (!intel_output)
		return;

	connector = &intel_output->base;
	drm_connector_init(dev, &intel_output->base,
			   &intel_crt_connector_funcs, DRM_MODE_CONNECTOR_VGA);

	drm_encoder_init(dev, &intel_output->enc, &intel_crt_enc_funcs,
			 DRM_MODE_ENCODER_DAC);

	drm_mode_connector_attach_encoder(&intel_output->base,
					  &intel_output->enc);

	/* Set up the DDC bus. */
	intel_output->ddc_bus = intel_i2c_create(dev, GPIOA, "CRTDDC_A");
	if (!intel_output->ddc_bus) {
		dev_printk(KERN_ERR, &dev->pdev->dev, "DDC bus registration "
			   "failed.\n");
		return;
	}

	intel_output->type = INTEL_OUTPUT_ANALOG;
	connector->interlace_allowed = 0;
	connector->doublescan_allowed = 0;

	drm_encoder_helper_add(&intel_output->enc, &intel_crt_helper_funcs);
	drm_connector_helper_add(connector, &intel_crt_connector_helper_funcs);

	drm_connector_register(connector);
}]]></programlisting>
      <para>
        In the example above (taken from the i915 driver), a CRTC, connector and
        encoder combination is created. A device-specific i2c bus is also
        created for fetching EDID data and performing monitor detection. Once
        the process is complete, the new connector is registered with sysfs to
        make its properties available to applications.
      </para>
    </sect2>
    <sect2>
      <title>KMS API Functions</title>
!Edrivers/gpu/drm/drm_crtc.c
    </sect2>
    <sect2>
      <title>KMS Locking</title>
!Pdrivers/gpu/drm/drm_modeset_lock.c kms locking
!Iinclude/drm/drm_modeset_lock.h
!Edrivers/gpu/drm/drm_modeset_lock.c
    </sect2>
  </sect1>

  <!-- Internals: kms helper functions -->

  <sect1>
    <title>Mode Setting Helper Functions</title>
    <para>
      The plane, CRTC, encoder and connector functions provided by the drivers
      implement the DRM API. They're called by the DRM core and ioctl handlers
      to handle device state changes and configuration request. As implementing
      those functions often requires logic not specific to drivers, mid-layer
      helper functions are available to avoid duplicating boilerplate code.
    </para>
    <para>
      The DRM core contains one mid-layer implementation. The mid-layer provides
      implementations of several plane, CRTC, encoder and connector functions
      (called from the top of the mid-layer) that pre-process requests and call
      lower-level functions provided by the driver (at the bottom of the
      mid-layer). For instance, the
      <function>drm_crtc_helper_set_config</function> function can be used to
      fill the struct <structname>drm_crtc_funcs</structname>
      <structfield>set_config</structfield> field. When called, it will split
      the <methodname>set_config</methodname> operation in smaller, simpler
      operations and call the driver to handle them.
    </para>
    <para>
      To use the mid-layer, drivers call <function>drm_crtc_helper_add</function>,
      <function>drm_encoder_helper_add</function> and
      <function>drm_connector_helper_add</function> functions to install their
      mid-layer bottom operations handlers, and fill the
      <structname>drm_crtc_funcs</structname>,
      <structname>drm_encoder_funcs</structname> and
      <structname>drm_connector_funcs</structname> structures with pointers to
      the mid-layer top API functions. Installing the mid-layer bottom operation
      handlers is best done right after registering the corresponding KMS object.
    </para>
    <para>
      The mid-layer is not split between CRTC, encoder and connector operations.
      To use it, a driver must provide bottom functions for all of the three KMS
      entities.
    </para>
    <sect2>
      <title>Helper Functions</title>
      <itemizedlist>
        <listitem>
          <synopsis>int drm_crtc_helper_set_config(struct drm_mode_set *set);</synopsis>
          <para>
            The <function>drm_crtc_helper_set_config</function> helper function
            is a CRTC <methodname>set_config</methodname> implementation. It
            first tries to locate the best encoder for each connector by calling
            the connector <methodname>best_encoder</methodname> helper
            operation.
          </para>
          <para>
            After locating the appropriate encoders, the helper function will
            call the <methodname>mode_fixup</methodname> encoder and CRTC helper
            operations to adjust the requested mode, or reject it completely in
            which case an error will be returned to the application. If the new
            configuration after mode adjustment is identical to the current
            configuration the helper function will return without performing any
            other operation.
          </para>
          <para>
            If the adjusted mode is identical to the current mode but changes to
            the frame buffer need to be applied, the
            <function>drm_crtc_helper_set_config</function> function will call
            the CRTC <methodname>mode_set_base</methodname> helper operation. If
            the adjusted mode differs from the current mode, or if the
            <methodname>mode_set_base</methodname> helper operation is not
            provided, the helper function performs a full mode set sequence by
            calling the <methodname>prepare</methodname>,
            <methodname>mode_set</methodname> and
            <methodname>commit</methodname> CRTC and encoder helper operations,
            in that order.
          </para>
        </listitem>
        <listitem>
          <synopsis>void drm_helper_connector_dpms(struct drm_connector *connector, int mode);</synopsis>
          <para>
            The <function>drm_helper_connector_dpms</function> helper function
            is a connector <methodname>dpms</methodname> implementation that
            tracks power state of connectors. To use the function, drivers must
            provide <methodname>dpms</methodname> helper operations for CRTCs
            and encoders to apply the DPMS state to the device.
          </para>
          <para>
            The mid-layer doesn't track the power state of CRTCs and encoders.
            The <methodname>dpms</methodname> helper operations can thus be
            called with a mode identical to the currently active mode.
          </para>
        </listitem>
        <listitem>
          <synopsis>int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
                                            uint32_t maxX, uint32_t maxY);</synopsis>
          <para>
            The <function>drm_helper_probe_single_connector_modes</function> helper
            function is a connector <methodname>fill_modes</methodname>
            implementation that updates the connection status for the connector
            and then retrieves a list of modes by calling the connector
            <methodname>get_modes</methodname> helper operation.
          </para>
          <para>
            The function filters out modes larger than
            <parameter>max_width</parameter> and <parameter>max_height</parameter>
            if specified. It then calls the optional connector
            <methodname>mode_valid</methodname> helper operation for each mode in
            the probed list to check whether the mode is valid for the connector.
          </para>
        </listitem>
      </itemizedlist>
    </sect2>
    <sect2>
      <title>CRTC Helper Operations</title>
      <itemizedlist>
        <listitem id="drm-helper-crtc-mode-fixup">
          <synopsis>bool (*mode_fixup)(struct drm_crtc *crtc,
                       const struct drm_display_mode *mode,
                       struct drm_display_mode *adjusted_mode);</synopsis>
          <para>
            Let CRTCs adjust the requested mode or reject it completely. This
            operation returns true if the mode is accepted (possibly after being
            adjusted) or false if it is rejected.
          </para>
          <para>
            The <methodname>mode_fixup</methodname> operation should reject the
            mode if it can't reasonably use it. The definition of "reasonable"
            is currently fuzzy in this context. One possible behaviour would be
            to set the adjusted mode to the panel timings when a fixed-mode
            panel is used with hardware capable of scaling. Another behaviour
            would be to accept any input mode and adjust it to the closest mode
            supported by the hardware (FIXME: This needs to be clarified).
          </para>
        </listitem>
        <listitem>
          <synopsis>int (*mode_set_base)(struct drm_crtc *crtc, int x, int y,
                     struct drm_framebuffer *old_fb)</synopsis>
          <para>
            Move the CRTC on the current frame buffer (stored in
            <literal>crtc-&gt;fb</literal>) to position (x,y). Any of the frame
            buffer, x position or y position may have been modified.
          </para>
          <para>
            This helper operation is optional. If not provided, the
            <function>drm_crtc_helper_set_config</function> function will fall
            back to the <methodname>mode_set</methodname> helper operation.
          </para>
          <note><para>
            FIXME: Why are x and y passed as arguments, as they can be accessed
            through <literal>crtc-&gt;x</literal> and
            <literal>crtc-&gt;y</literal>?
          </para></note>
        </listitem>
        <listitem>
          <synopsis>void (*prepare)(struct drm_crtc *crtc);</synopsis>
          <para>
            Prepare the CRTC for mode setting. This operation is called after
            validating the requested mode. Drivers use it to perform
            device-specific operations required before setting the new mode.
          </para>
        </listitem>
        <listitem>
          <synopsis>int (*mode_set)(struct drm_crtc *crtc, struct drm_display_mode *mode,
                struct drm_display_mode *adjusted_mode, int x, int y,
                struct drm_framebuffer *old_fb);</synopsis>
          <para>
            Set a new mode, position and frame buffer. Depending on the device
            requirements, the mode can be stored internally by the driver and
            applied in the <methodname>commit</methodname> operation, or
            programmed to the hardware immediately.
          </para>
          <para>
            The <methodname>mode_set</methodname> operation returns 0 on success
	    or a negative error code if an error occurs.
          </para>
        </listitem>
        <listitem>
          <synopsis>void (*commit)(struct drm_crtc *crtc);</synopsis>
          <para>
            Commit a mode. This operation is called after setting the new mode.
            Upon return the device must use the new mode and be fully
            operational.
          </para>
        </listitem>
      </itemizedlist>
    </sect2>
    <sect2>
      <title>Encoder Helper Operations</title>
      <itemizedlist>
        <listitem>
          <synopsis>bool (*mode_fixup)(struct drm_encoder *encoder,
                       const struct drm_display_mode *mode,
                       struct drm_display_mode *adjusted_mode);</synopsis>
          <para>
            Let encoders adjust the requested mode or reject it completely. This
            operation returns true if the mode is accepted (possibly after being
            adjusted) or false if it is rejected. See the
            <link linkend="drm-helper-crtc-mode-fixup">mode_fixup CRTC helper
            operation</link> for an explanation of the allowed adjustments.
          </para>
        </listitem>
        <listitem>
          <synopsis>void (*prepare)(struct drm_encoder *encoder);</synopsis>
          <para>
            Prepare the encoder for mode setting. This operation is called after
            validating the requested mode. Drivers use it to perform
            device-specific operations required before setting the new mode.
          </para>
        </listitem>
        <listitem>
          <synopsis>void (*mode_set)(struct drm_encoder *encoder,
                 struct drm_display_mode *mode,
                 struct drm_display_mode *adjusted_mode);</synopsis>
          <para>
            Set a new mode. Depending on the device requirements, the mode can
            be stored internally by the driver and applied in the
            <methodname>commit</methodname> operation, or programmed to the
            hardware immediately.
          </para>
        </listitem>
        <listitem>
          <synopsis>void (*commit)(struct drm_encoder *encoder);</synopsis>
          <para>
            Commit a mode. This operation is called after setting the new mode.
            Upon return the device must use the new mode and be fully
            operational.
          </para>
        </listitem>
      </itemizedlist>
    </sect2>
    <sect2>
      <title>Connector Helper Operations</title>
      <itemizedlist>
        <listitem>
          <synopsis>struct drm_encoder *(*best_encoder)(struct drm_connector *connector);</synopsis>
          <para>
            Return a pointer to the best encoder for the connecter. Device that
            map connectors to encoders 1:1 simply return the pointer to the
            associated encoder. This operation is mandatory.
          </para>
        </listitem>
        <listitem>
          <synopsis>int (*get_modes)(struct drm_connector *connector);</synopsis>
          <para>
            Fill the connector's <structfield>probed_modes</structfield> list
            by parsing EDID data with <function>drm_add_edid_modes</function> or
            calling <function>drm_mode_probed_add</function> directly for every
            supported mode and return the number of modes it has detected. This
            operation is mandatory.
          </para>
          <para>
            When adding modes manually the driver creates each mode with a call to
            <function>drm_mode_create</function> and must fill the following fields.
            <itemizedlist>
              <listitem>
                <synopsis>__u32 type;</synopsis>
                <para>
                  Mode type bitmask, a combination of
                  <variablelist>
                    <varlistentry>
                      <term>DRM_MODE_TYPE_BUILTIN</term>
                      <listitem><para>not used?</para></listitem>
                    </varlistentry>
                    <varlistentry>
                      <term>DRM_MODE_TYPE_CLOCK_C</term>
                      <listitem><para>not used?</para></listitem>
                    </varlistentry>
                    <varlistentry>
                      <term>DRM_MODE_TYPE_CRTC_C</term>
                      <listitem><para>not used?</para></listitem>
                    </varlistentry>
                    <varlistentry>
                      <term>
        DRM_MODE_TYPE_PREFERRED - The preferred mode for the connector
                      </term>
                      <listitem>
                        <para>not used?</para>
                      </listitem>
                    </varlistentry>
                    <varlistentry>
                      <term>DRM_MODE_TYPE_DEFAULT</term>
                      <listitem><para>not used?</para></listitem>
                    </varlistentry>
                    <varlistentry>
                      <term>DRM_MODE_TYPE_USERDEF</term>
                      <listitem><para>not used?</para></listitem>
                    </varlistentry>
                    <varlistentry>
                      <term>DRM_MODE_TYPE_DRIVER</term>
                      <listitem>
                        <para>
                          The mode has been created by the driver (as opposed to
                          to user-created modes).
                        </para>
                      </listitem>
                    </varlistentry>
                  </variablelist>
                  Drivers must set the DRM_MODE_TYPE_DRIVER bit for all modes they
                  create, and set the DRM_MODE_TYPE_PREFERRED bit for the preferred
                  mode.
                </para>
              </listitem>
              <listitem>
                <synopsis>__u32 clock;</synopsis>
                <para>Pixel clock frequency in kHz unit</para>
              </listitem>
              <listitem>
                <synopsis>__u16 hdisplay, hsync_start, hsync_end, htotal;
    __u16 vdisplay, vsync_start, vsync_end, vtotal;</synopsis>
                <para>Horizontal and vertical timing information</para>
                <screen><![CDATA[
             Active                 Front           Sync           Back
             Region                 Porch                          Porch
    <-----------------------><----------------><-------------><-------------->

      //////////////////////|
     ////////////////////// |
    //////////////////////  |..................               ................
                                               _______________

    <----- [hv]display ----->
    <------------- [hv]sync_start ------------>
    <--------------------- [hv]sync_end --------------------->
    <-------------------------------- [hv]total ----------------------------->
]]></screen>
              </listitem>
              <listitem>
                <synopsis>__u16 hskew;
    __u16 vscan;</synopsis>
                <para>Unknown</para>
              </listitem>
              <listitem>
                <synopsis>__u32 flags;</synopsis>
                <para>
                  Mode flags, a combination of
                  <variablelist>
                    <varlistentry>
                      <term>DRM_MODE_FLAG_PHSYNC</term>
                      <listitem><para>
                        Horizontal sync is active high
                      </para></listitem>
                    </varlistentry>
                    <varlistentry>
                      <term>DRM_MODE_FLAG_NHSYNC</term>
                      <listitem><para>
                        Horizontal sync is active low
                      </para></listitem>
                    </varlistentry>
                    <varlistentry>
                      <term>DRM_MODE_FLAG_PVSYNC</term>
                      <listitem><para>
                        Vertical sync is active high
                      </para></listitem>
                    </varlistentry>
                    <varlistentry>
                      <term>DRM_MODE_FLAG_NVSYNC</term>
                      <listitem><para>
                        Vertical sync is active low
                      </para></listitem>
                    </varlistentry>
                    <varlistentry>
                      <term>DRM_MODE_FLAG_INTERLACE</term>
                      <listitem><para>
                        Mode is interlaced
                      </para></listitem>
                    </varlistentry>
                    <varlistentry>
                      <term>DRM_MODE_FLAG_DBLSCAN</term>
                      <listitem><para>
                        Mode uses doublescan
                      </para></listitem>
                    </varlistentry>
                    <varlistentry>
                      <term>DRM_MODE_FLAG_CSYNC</term>
                      <listitem><para>
                        Mode uses composite sync
                      </para></listitem>
                    </varlistentry>
                    <varlistentry>
                      <term>DRM_MODE_FLAG_PCSYNC</term>
                      <listitem><para>
                        Composite sync is active high
                      </para></listitem>
                    </varlistentry>
                    <varlistentry>
                      <term>DRM_MODE_FLAG_NCSYNC</term>
                      <listitem><para>
                        Composite sync is active low
                      </para></listitem>
                    </varlistentry>
                    <varlistentry>
                      <term>DRM_MODE_FLAG_HSKEW</term>
                      <listitem><para>
                        hskew provided (not used?)
                      </para></listitem>
                    </varlistentry>
                    <varlistentry>
                      <term>DRM_MODE_FLAG_BCAST</term>
                      <listitem><para>
                        not used?
                      </para></listitem>
                    </varlistentry>
                    <varlistentry>
                      <term>DRM_MODE_FLAG_PIXMUX</term>
                      <listitem><para>
                        not used?
                      </para></listitem>
                    </varlistentry>
                    <varlistentry>
                      <term>DRM_MODE_FLAG_DBLCLK</term>
                      <listitem><para>
                        not used?
                      </para></listitem>
                    </varlistentry>
                    <varlistentry>
                      <term>DRM_MODE_FLAG_CLKDIV2</term>
                      <listitem><para>
                        ?
                      </para></listitem>
                    </varlistentry>
                  </variablelist>
                </para>
                <para>
                  Note that modes marked with the INTERLACE or DBLSCAN flags will be
                  filtered out by
                  <function>drm_helper_probe_single_connector_modes</function> if
                  the connector's <structfield>interlace_allowed</structfield> or
                  <structfield>doublescan_allowed</structfield> field is set to 0.
                </para>
              </listitem>
              <listitem>
                <synopsis>char name[DRM_DISPLAY_MODE_LEN];</synopsis>
                <para>
                  Mode name. The driver must call
                  <function>drm_mode_set_name</function> to fill the mode name from
                  <structfield>hdisplay</structfield>,
                  <structfield>vdisplay</structfield> and interlace flag after
                  filling the corresponding fields.
                </para>
              </listitem>
            </itemizedlist>
          </para>
          <para>
            The <structfield>vrefresh</structfield> value is computed by
            <function>drm_helper_probe_single_connector_modes</function>.
          </para>
          <para>
            When parsing EDID data, <function>drm_add_edid_modes</function> fill the
            connector <structfield>display_info</structfield>
            <structfield>width_mm</structfield> and
            <structfield>height_mm</structfield> fields. When creating modes
            manually the <methodname>get_modes</methodname> helper operation must
            set the <structfield>display_info</structfield>
            <structfield>width_mm</structfield> and
            <structfield>height_mm</structfield> fields if they haven't been set
            already (for instance at initialization time when a fixed-size panel is
            attached to the connector). The mode <structfield>width_mm</structfield>
            and <structfield>height_mm</structfield> fields are only used internally
            during EDID parsing and should not be set when creating modes manually.
          </para>
        </listitem>
        <listitem>
          <synopsis>int (*mode_valid)(struct drm_connector *connector,
		  struct drm_display_mode *mode);</synopsis>
          <para>
            Verify whether a mode is valid for the connector. Return MODE_OK for
            supported modes and one of the enum drm_mode_status values (MODE_*)
            for unsupported modes. This operation is optional.
          </para>
          <para>
            As the mode rejection reason is currently not used beside for
            immediately removing the unsupported mode, an implementation can
            return MODE_BAD regardless of the exact reason why the mode is not
            valid.
          </para>
          <note><para>
            Note that the <methodname>mode_valid</methodname> helper operation is
            only called for modes detected by the device, and
            <emphasis>not</emphasis> for modes set by the user through the CRTC
            <methodname>set_config</methodname> operation.
          </para></note>
        </listitem>
      </itemizedlist>
    </sect2>
    <sect2>
      <title>Modeset Helper Functions Reference</title>
!Edrivers/gpu/drm/drm_crtc_helper.c
    </sect2>
    <sect2>
      <title>Output Probing Helper Functions Reference</title>
!Pdrivers/gpu/drm/drm_probe_helper.c output probing helper overview
!Edrivers/gpu/drm/drm_probe_helper.c
    </sect2>
    <sect2>
      <title>fbdev Helper Functions Reference</title>
!Pdrivers/gpu/drm/drm_fb_helper.c fbdev helpers
!Edrivers/gpu/drm/drm_fb_helper.c
!Iinclude/drm/drm_fb_helper.h
    </sect2>
    <sect2>
      <title>Display Port Helper Functions Reference</title>
!Pdrivers/gpu/drm/drm_dp_helper.c dp helpers
!Iinclude/drm/drm_dp_helper.h
!Edrivers/gpu/drm/drm_dp_helper.c
    </sect2>
    <sect2>
      <title>Display Port MST Helper Functions Reference</title>
!Pdrivers/gpu/drm/drm_dp_mst_topology.c dp mst helper
!Iinclude/drm/drm_dp_mst_helper.h
!Edrivers/gpu/drm/drm_dp_mst_topology.c
    </sect2>
    <sect2>
      <title>EDID Helper Functions Reference</title>
!Edrivers/gpu/drm/drm_edid.c
    </sect2>
    <sect2>
      <title>Rectangle Utilities Reference</title>
!Pinclude/drm/drm_rect.h rect utils
!Iinclude/drm/drm_rect.h
!Edrivers/gpu/drm/drm_rect.c
    </sect2>
    <sect2>
      <title>Flip-work Helper Reference</title>
!Pinclude/drm/drm_flip_work.h flip utils
!Iinclude/drm/drm_flip_work.h
!Edrivers/gpu/drm/drm_flip_work.c
    </sect2>
    <sect2>
      <title>HDMI Infoframes Helper Reference</title>
      <para>
	Strictly speaking this is not a DRM helper library but generally useable
	by any driver interfacing with HDMI outputs like v4l or alsa drivers.
	But it nicely fits into the overall topic of mode setting helper
	libraries and hence is also included here.
      </para>
!Iinclude/linux/hdmi.h
!Edrivers/video/hdmi.c
    </sect2>
    <sect2>
      <title id="drm-kms-planehelpers">Plane Helper Reference</title>
!Edrivers/gpu/drm/drm_plane_helper.c Plane Helpers
    </sect2>
  </sect1>

  <!-- Internals: kms properties -->

  <sect1 id="drm-kms-properties">
    <title>KMS Properties</title>
    <para>
      Drivers may need to expose additional parameters to applications than
      those described in the previous sections. KMS supports attaching
      properties to CRTCs, connectors and planes and offers a userspace API to
      list, get and set the property values.
    </para>
    <para>
      Properties are identified by a name that uniquely defines the property
      purpose, and store an associated value. For all property types except blob
      properties the value is a 64-bit unsigned integer.
    </para>
    <para>
      KMS differentiates between properties and property instances. Drivers
      first create properties and then create and associate individual instances
      of those properties to objects. A property can be instantiated multiple
      times and associated with different objects. Values are stored in property
      instances, and all other property information are stored in the property
      and shared between all instances of the property.
    </para>
    <para>
      Every property is created with a type that influences how the KMS core
      handles the property. Supported property types are
      <variablelist>
        <varlistentry>
          <term>DRM_MODE_PROP_RANGE</term>
          <listitem><para>Range properties report their minimum and maximum
            admissible values. The KMS core verifies that values set by
            application fit in that range.</para></listitem>
        </varlistentry>
        <varlistentry>
          <term>DRM_MODE_PROP_ENUM</term>
          <listitem><para>Enumerated properties take a numerical value that
            ranges from 0 to the number of enumerated values defined by the
            property minus one, and associate a free-formed string name to each
            value. Applications can retrieve the list of defined value-name pairs
            and use the numerical value to get and set property instance values.
            </para></listitem>
        </varlistentry>
        <varlistentry>
          <term>DRM_MODE_PROP_BITMASK</term>
          <listitem><para>Bitmask properties are enumeration properties that
            additionally restrict all enumerated values to the 0..63 range.
            Bitmask property instance values combine one or more of the
            enumerated bits defined by the property.</para></listitem>
        </varlistentry>
        <varlistentry>
          <term>DRM_MODE_PROP_BLOB</term>
          <listitem><para>Blob properties store a binary blob without any format
            restriction. The binary blobs are created as KMS standalone objects,
            and blob property instance values store the ID of their associated
            blob object.</para>
	    <para>Blob properties are only used for the connector EDID property
	    and cannot be created by drivers.</para></listitem>
        </varlistentry>
      </variablelist>
    </para>
    <para>
      To create a property drivers call one of the following functions depending
      on the property type. All property creation functions take property flags
      and name, as well as type-specific arguments.
      <itemizedlist>
        <listitem>
          <synopsis>struct drm_property *drm_property_create_range(struct drm_device *dev, int flags,
                                               const char *name,
                                               uint64_t min, uint64_t max);</synopsis>
          <para>Create a range property with the given minimum and maximum
            values.</para>
        </listitem>
        <listitem>
          <synopsis>struct drm_property *drm_property_create_enum(struct drm_device *dev, int flags,
                                              const char *name,
                                              const struct drm_prop_enum_list *props,
                                              int num_values);</synopsis>
          <para>Create an enumerated property. The <parameter>props</parameter>
            argument points to an array of <parameter>num_values</parameter>
            value-name pairs.</para>
        </listitem>
        <listitem>
          <synopsis>struct drm_property *drm_property_create_bitmask(struct drm_device *dev,
                                                 int flags, const char *name,
                                                 const struct drm_prop_enum_list *props,
                                                 int num_values);</synopsis>
          <para>Create a bitmask property. The <parameter>props</parameter>
            argument points to an array of <parameter>num_values</parameter>
            value-name pairs.</para>
        </listitem>
      </itemizedlist>
    </para>
    <para>
      Properties can additionally be created as immutable, in which case they
      will be read-only for applications but can be modified by the driver. To
      create an immutable property drivers must set the DRM_MODE_PROP_IMMUTABLE
      flag at property creation time.
    </para>
    <para>
      When no array of value-name pairs is readily available at property
      creation time for enumerated or range properties, drivers can create
      the property using the <function>drm_property_create</function> function
      and manually add enumeration value-name pairs by calling the
      <function>drm_property_add_enum</function> function. Care must be taken to
      properly specify the property type through the <parameter>flags</parameter>
      argument.
    </para>
    <para>
      After creating properties drivers can attach property instances to CRTC,
      connector and plane objects by calling the
      <function>drm_object_attach_property</function>. The function takes a
      pointer to the target object, a pointer to the previously created property
      and an initial instance value.
    </para>
    <sect2>
	<title>Existing KMS Properties</title>
	<para>
	The following table gives description of drm properties exposed by various
	modules/drivers.
	</para>
	<table border="1" cellpadding="0" cellspacing="0">
	<tbody>
	<tr style="font-weight: bold;">
	<td valign="top" >Owner Module/Drivers</td>
	<td valign="top" >Group</td>
	<td valign="top" >Property Name</td>
	<td valign="top" >Type</td>
	<td valign="top" >Property Values</td>
	<td valign="top" >Object attached</td>
	<td valign="top" >Description/Restrictions</td>
	</tr>
	<tr>
	<td rowspan="21" valign="top" >DRM</td>
	<td rowspan="2" valign="top" >Generic</td>
	<td valign="top" >“EDID”</td>
	<td valign="top" >BLOB | IMMUTABLE</td>
	<td valign="top" >0</td>
	<td valign="top" >Connector</td>
	<td valign="top" >Contains id of edid blob ptr object.</td>
	</tr>
	<tr>
	<td valign="top" >“DPMS”</td>
	<td valign="top" >ENUM</td>
	<td valign="top" >{ “On”, “Standby”, “Suspend”, “Off” }</td>
	<td valign="top" >Connector</td>
	<td valign="top" >Contains DPMS operation mode value.</td>
	</tr>
	<tr>
	<td rowspan="1" valign="top" >Plane</td>
	<td valign="top" >“type”</td>
	<td valign="top" >ENUM | IMMUTABLE</td>
	<td valign="top" >{ "Overlay", "Primary", "Cursor" }</td>
	<td valign="top" >Plane</td>
	<td valign="top" >Plane type</td>
	</tr>
	<tr>
	<td rowspan="2" valign="top" >DVI-I</td>
	<td valign="top" >“subconnector”</td>
	<td valign="top" >ENUM</td>
	<td valign="top" >{ “Unknown”, “DVI-D”, “DVI-A” }</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“select subconnector”</td>
	<td valign="top" >ENUM</td>
	<td valign="top" >{ “Automatic”, “DVI-D”, “DVI-A” }</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td rowspan="13" valign="top" >TV</td>
	<td valign="top" >“subconnector”</td>
	<td valign="top" >ENUM</td>
	<td valign="top" >{ "Unknown", "Composite", "SVIDEO", "Component", "SCART" }</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“select subconnector”</td>
	<td valign="top" >ENUM</td>
	<td valign="top" >{ "Automatic", "Composite", "SVIDEO", "Component", "SCART" }</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“mode”</td>
	<td valign="top" >ENUM</td>
	<td valign="top" >{ "NTSC_M", "NTSC_J", "NTSC_443", "PAL_B" } etc.</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“left margin”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=100</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“right margin”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=100</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“top margin”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=100</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“bottom margin”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=100</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“brightness”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=100</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“contrast”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=100</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“flicker reduction”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=100</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“overscan”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=100</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“saturation”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=100</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“hue”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=100</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td rowspan="3" valign="top" >Optional</td>
	<td valign="top" >“scaling mode”</td>
	<td valign="top" >ENUM</td>
	<td valign="top" >{ "None", "Full", "Center", "Full aspect" }</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >"aspect ratio"</td>
	<td valign="top" >ENUM</td>
	<td valign="top" >{ "None", "4:3", "16:9" }</td>
	<td valign="top" >Connector</td>
	<td valign="top" >DRM property to set aspect ratio from user space app.
		This enum is made generic to allow addition of custom aspect
		ratios.</td>
	</tr>
	<tr>
	<td valign="top" >“dirty”</td>
	<td valign="top" >ENUM | IMMUTABLE</td>
	<td valign="top" >{ "Off", "On", "Annotate" }</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td rowspan="21" valign="top" >i915</td>
	<td rowspan="2" valign="top" >Generic</td>
	<td valign="top" >"Broadcast RGB"</td>
	<td valign="top" >ENUM</td>
	<td valign="top" >{ "Automatic", "Full", "Limited 16:235" }</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“audio”</td>
	<td valign="top" >ENUM</td>
	<td valign="top" >{ "force-dvi", "off", "auto", "on" }</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td rowspan="1" valign="top" >Plane</td>
	<td valign="top" >“rotation”</td>
	<td valign="top" >BITMASK</td>
	<td valign="top" >{ 0, "rotate-0" }, { 2, "rotate-180" }</td>
	<td valign="top" >Plane</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td rowspan="17" valign="top" >SDVO-TV</td>
	<td valign="top" >“mode”</td>
	<td valign="top" >ENUM</td>
	<td valign="top" >{ "NTSC_M", "NTSC_J", "NTSC_443", "PAL_B" } etc.</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >"left_margin"</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >"right_margin"</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >"top_margin"</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >"bottom_margin"</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“hpos”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“vpos”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“contrast”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“saturation”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“hue”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“sharpness”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“flicker_filter”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“flicker_filter_adaptive”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“flicker_filter_2d”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“tv_chroma_filter”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“tv_luma_filter”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“dot_crawl”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=1</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >SDVO-TV/LVDS</td>
	<td valign="top" >“brightness”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td rowspan="2" valign="top" >CDV gma-500</td>
	<td rowspan="2" valign="top" >Generic</td>
	<td valign="top" >"Broadcast RGB"</td>
	<td valign="top" >ENUM</td>
	<td valign="top" >{ “Full”, “Limited 16:235” }</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >"Broadcast RGB"</td>
	<td valign="top" >ENUM</td>
	<td valign="top" >{ “off”, “auto”, “on” }</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td rowspan="19" valign="top" >Poulsbo</td>
	<td rowspan="1" valign="top" >Generic</td>
	<td valign="top" >“backlight”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=100</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td rowspan="17" valign="top" >SDVO-TV</td>
	<td valign="top" >“mode”</td>
	<td valign="top" >ENUM</td>
	<td valign="top" >{ "NTSC_M", "NTSC_J", "NTSC_443", "PAL_B" } etc.</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >"left_margin"</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >"right_margin"</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >"top_margin"</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >"bottom_margin"</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“hpos”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“vpos”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“contrast”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“saturation”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“hue”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“sharpness”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“flicker_filter”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“flicker_filter_adaptive”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“flicker_filter_2d”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“tv_chroma_filter”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“tv_luma_filter”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“dot_crawl”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=1</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >SDVO-TV/LVDS</td>
	<td valign="top" >“brightness”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max= SDVO dependent</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td rowspan="11" valign="top" >armada</td>
	<td rowspan="2" valign="top" >CRTC</td>
	<td valign="top" >"CSC_YUV"</td>
	<td valign="top" >ENUM</td>
	<td valign="top" >{ "Auto" , "CCIR601", "CCIR709" }</td>
	<td valign="top" >CRTC</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >"CSC_RGB"</td>
	<td valign="top" >ENUM</td>
	<td valign="top" >{ "Auto", "Computer system", "Studio" }</td>
	<td valign="top" >CRTC</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td rowspan="9" valign="top" >Overlay</td>
	<td valign="top" >"colorkey"</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=0xffffff</td>
	<td valign="top" >Plane</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >"colorkey_min"</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=0xffffff</td>
	<td valign="top" >Plane</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >"colorkey_max"</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=0xffffff</td>
	<td valign="top" >Plane</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >"colorkey_val"</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=0xffffff</td>
	<td valign="top" >Plane</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >"colorkey_alpha"</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=0xffffff</td>
	<td valign="top" >Plane</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >"colorkey_mode"</td>
	<td valign="top" >ENUM</td>
	<td valign="top" >{ "disabled", "Y component", "U component"
	, "V component", "RGB", “R component", "G component", "B component" }</td>
	<td valign="top" >Plane</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >"brightness"</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=256 + 255</td>
	<td valign="top" >Plane</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >"contrast"</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=0x7fff</td>
	<td valign="top" >Plane</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >"saturation"</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=0x7fff</td>
	<td valign="top" >Plane</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td rowspan="2" valign="top" >exynos</td>
	<td valign="top" >CRTC</td>
	<td valign="top" >“mode”</td>
	<td valign="top" >ENUM</td>
	<td valign="top" >{ "normal", "blank" }</td>
	<td valign="top" >CRTC</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >Overlay</td>
	<td valign="top" >“zpos”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=MAX_PLANE-1</td>
	<td valign="top" >Plane</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td rowspan="2" valign="top" >i2c/ch7006_drv</td>
	<td valign="top" >Generic</td>
	<td valign="top" >“scale”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=2</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td rowspan="1" valign="top" >TV</td>
	<td valign="top" >“mode”</td>
	<td valign="top" >ENUM</td>
	<td valign="top" >{ "PAL", "PAL-M","PAL-N"}, ”PAL-Nc"
	, "PAL-60", "NTSC-M", "NTSC-J" }</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td rowspan="15" valign="top" >nouveau</td>
	<td rowspan="6" valign="top" >NV10 Overlay</td>
	<td valign="top" >"colorkey"</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=0x01ffffff</td>
	<td valign="top" >Plane</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“contrast”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=8192-1</td>
	<td valign="top" >Plane</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“brightness”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=1024</td>
	<td valign="top" >Plane</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“hue”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=359</td>
	<td valign="top" >Plane</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“saturation”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=8192-1</td>
	<td valign="top" >Plane</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“iturbt_709”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=1</td>
	<td valign="top" >Plane</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td rowspan="2" valign="top" >Nv04 Overlay</td>
	<td valign="top" >“colorkey”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=0x01ffffff</td>
	<td valign="top" >Plane</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“brightness”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=1024</td>
	<td valign="top" >Plane</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td rowspan="7" valign="top" >Display</td>
	<td valign="top" >“dithering mode”</td>
	<td valign="top" >ENUM</td>
	<td valign="top" >{ "auto", "off", "on" }</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“dithering depth”</td>
	<td valign="top" >ENUM</td>
	<td valign="top" >{ "auto", "off", "on", "static 2x2", "dynamic 2x2", "temporal" }</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“underscan”</td>
	<td valign="top" >ENUM</td>
	<td valign="top" >{ "auto", "6 bpc", "8 bpc" }</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“underscan hborder”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=128</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“underscan vborder”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=128</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“vibrant hue”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=180</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“color vibrance”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=200</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td rowspan="2" valign="top" >omap</td>
	<td rowspan="2" valign="top" >Generic</td>
	<td valign="top" >“rotation”</td>
	<td valign="top" >BITMASK</td>
	<td valign="top" >{ 0, "rotate-0" },
	{ 1, "rotate-90" },
	{ 2, "rotate-180" },
	{ 3, "rotate-270" },
	{ 4, "reflect-x" },
	{ 5, "reflect-y" }</td>
	<td valign="top" >CRTC, Plane</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >“zorder”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=3</td>
	<td valign="top" >CRTC, Plane</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >qxl</td>
	<td valign="top" >Generic</td>
	<td valign="top" >“hotplug_mode_update"</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=1</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td rowspan="9" valign="top" >radeon</td>
	<td valign="top" >DVI-I</td>
	<td valign="top" >“coherent”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=1</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >DAC enable load detect</td>
	<td valign="top" >“load detection”</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=1</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >TV Standard</td>
	<td valign="top" >"tv standard"</td>
	<td valign="top" >ENUM</td>
	<td valign="top" >{ "ntsc", "pal", "pal-m", "pal-60", "ntsc-j"
	, "scart-pal", "pal-cn", "secam" }</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >legacy TMDS PLL detect</td>
	<td valign="top" >"tmds_pll"</td>
	<td valign="top" >ENUM</td>
	<td valign="top" >{ "driver", "bios" }</td>
	<td valign="top" >-</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td rowspan="3" valign="top" >Underscan</td>
	<td valign="top" >"underscan"</td>
	<td valign="top" >ENUM</td>
	<td valign="top" >{ "off", "on", "auto" }</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >"underscan hborder"</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=128</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >"underscan vborder"</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=128</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >Audio</td>
	<td valign="top" >“audio”</td>
	<td valign="top" >ENUM</td>
	<td valign="top" >{ "off", "on", "auto" }</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >FMT Dithering</td>
	<td valign="top" >“dither”</td>
	<td valign="top" >ENUM</td>
	<td valign="top" >{ "off", "on" }</td>
	<td valign="top" >Connector</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td rowspan="3" valign="top" >rcar-du</td>
	<td rowspan="3" valign="top" >Generic</td>
	<td valign="top" >"alpha"</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=255</td>
	<td valign="top" >Plane</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >"colorkey"</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=0, Max=0x01ffffff</td>
	<td valign="top" >Plane</td>
	<td valign="top" >TBD</td>
	</tr>
	<tr>
	<td valign="top" >"zpos"</td>
	<td valign="top" >RANGE</td>
	<td valign="top" >Min=1, Max=7</td>
	<td valign="top" >Plane</td>
	<td valign="top" >TBD</td>
	</tr>
	</tbody>
	</table>
    </sect2>
  </sect1>

  <!-- Internals: vertical blanking -->

  <sect1 id="drm-vertical-blank">
    <title>Vertical Blanking</title>
    <para>
      Vertical blanking plays a major role in graphics rendering. To achieve
      tear-free display, users must synchronize page flips and/or rendering to
      vertical blanking. The DRM API offers ioctls to perform page flips
      synchronized to vertical blanking and wait for vertical blanking.
    </para>
    <para>
      The DRM core handles most of the vertical blanking management logic, which
      involves filtering out spurious interrupts, keeping race-free blanking
      counters, coping with counter wrap-around and resets and keeping use
      counts. It relies on the driver to generate vertical blanking interrupts
      and optionally provide a hardware vertical blanking counter. Drivers must
      implement the following operations.
    </para>
    <itemizedlist>
      <listitem>
        <synopsis>int (*enable_vblank) (struct drm_device *dev, int crtc);
void (*disable_vblank) (struct drm_device *dev, int crtc);</synopsis>
        <para>
	  Enable or disable vertical blanking interrupts for the given CRTC.
	</para>
      </listitem>
      <listitem>
        <synopsis>u32 (*get_vblank_counter) (struct drm_device *dev, int crtc);</synopsis>
        <para>
	  Retrieve the value of the vertical blanking counter for the given
	  CRTC. If the hardware maintains a vertical blanking counter its value
	  should be returned. Otherwise drivers can use the
	  <function>drm_vblank_count</function> helper function to handle this
	  operation.
	</para>
      </listitem>
    </itemizedlist>
    <para>
      Drivers must initialize the vertical blanking handling core with a call to
      <function>drm_vblank_init</function> in their
      <methodname>load</methodname> operation. The function will set the struct
      <structname>drm_device</structname>
      <structfield>vblank_disable_allowed</structfield> field to 0. This will
      keep vertical blanking interrupts enabled permanently until the first mode
      set operation, where <structfield>vblank_disable_allowed</structfield> is
      set to 1. The reason behind this is not clear. Drivers can set the field
      to 1 after <function>calling drm_vblank_init</function> to make vertical
      blanking interrupts dynamically managed from the beginning.
    </para>
    <para>
      Vertical blanking interrupts can be enabled by the DRM core or by drivers
      themselves (for instance to handle page flipping operations). The DRM core
      maintains a vertical blanking use count to ensure that the interrupts are
      not disabled while a user still needs them. To increment the use count,
      drivers call <function>drm_vblank_get</function>. Upon return vertical
      blanking interrupts are guaranteed to be enabled.
    </para>
    <para>
      To decrement the use count drivers call
      <function>drm_vblank_put</function>. Only when the use count drops to zero
      will the DRM core disable the vertical blanking interrupts after a delay
      by scheduling a timer. The delay is accessible through the vblankoffdelay
      module parameter or the <varname>drm_vblank_offdelay</varname> global
      variable and expressed in milliseconds. Its default value is 5000 ms.
    </para>
    <para>
      When a vertical blanking interrupt occurs drivers only need to call the
      <function>drm_handle_vblank</function> function to account for the
      interrupt.
    </para>
    <para>
      Resources allocated by <function>drm_vblank_init</function> must be freed
      with a call to <function>drm_vblank_cleanup</function> in the driver
      <methodname>unload</methodname> operation handler.
    </para>
    <sect2>
      <title>Vertical Blanking and Interrupt Handling Functions Reference</title>
!Edrivers/gpu/drm/drm_irq.c
!Iinclude/drm/drmP.h drm_crtc_vblank_waitqueue
    </sect2>
  </sect1>

  <!-- Internals: open/close, file operations and ioctls -->

  <sect1>
    <title>Open/Close, File Operations and IOCTLs</title>
    <sect2>
      <title>Open and Close</title>
      <synopsis>int (*firstopen) (struct drm_device *);
void (*lastclose) (struct drm_device *);
int (*open) (struct drm_device *, struct drm_file *);
void (*preclose) (struct drm_device *, struct drm_file *);
void (*postclose) (struct drm_device *, struct drm_file *);</synopsis>
      <abstract>Open and close handlers. None of those methods are mandatory.
      </abstract>
      <para>
        The <methodname>firstopen</methodname> method is called by the DRM core
	for legacy UMS (User Mode Setting) drivers only when an application
	opens a device that has no other opened file handle. UMS drivers can
	implement it to acquire device resources. KMS drivers can't use the
	method and must acquire resources in the <methodname>load</methodname>
	method instead.
      </para>
      <para>
	Similarly the <methodname>lastclose</methodname> method is called when
	the last application holding a file handle opened on the device closes
	it, for both UMS and KMS drivers. Additionally, the method is also
	called at module unload time or, for hot-pluggable devices, when the
	device is unplugged. The <methodname>firstopen</methodname> and
	<methodname>lastclose</methodname> calls can thus be unbalanced.
      </para>
      <para>
        The <methodname>open</methodname> method is called every time the device
	is opened by an application. Drivers can allocate per-file private data
	in this method and store them in the struct
	<structname>drm_file</structname> <structfield>driver_priv</structfield>
	field. Note that the <methodname>open</methodname> method is called
	before <methodname>firstopen</methodname>.
      </para>
      <para>
        The close operation is split into <methodname>preclose</methodname> and
	<methodname>postclose</methodname> methods. Drivers must stop and
	cleanup all per-file operations in the <methodname>preclose</methodname>
	method. For instance pending vertical blanking and page flip events must
	be cancelled. No per-file operation is allowed on the file handle after
	returning from the <methodname>preclose</methodname> method.
      </para>
      <para>
        Finally the <methodname>postclose</methodname> method is called as the
	last step of the close operation, right before calling the
	<methodname>lastclose</methodname> method if no other open file handle
	exists for the device. Drivers that have allocated per-file private data
	in the <methodname>open</methodname> method should free it here.
      </para>
      <para>
        The <methodname>lastclose</methodname> method should restore CRTC and
	plane properties to default value, so that a subsequent open of the
	device will not inherit state from the previous user. It can also be
	used to execute delayed power switching state changes, e.g. in
	conjunction with the vga-switcheroo infrastructure. Beyond that KMS
	drivers should not do any further cleanup. Only legacy UMS drivers might
	need to clean up device state so that the vga console or an independent
	fbdev driver could take over.
      </para>
    </sect2>
    <sect2>
      <title>File Operations</title>
      <synopsis>const struct file_operations *fops</synopsis>
      <abstract>File operations for the DRM device node.</abstract>
      <para>
        Drivers must define the file operations structure that forms the DRM
	userspace API entry point, even though most of those operations are
	implemented in the DRM core. The <methodname>open</methodname>,
	<methodname>release</methodname> and <methodname>ioctl</methodname>
	operations are handled by
	<programlisting>
	.owner = THIS_MODULE,
	.open = drm_open,
	.release = drm_release,
	.unlocked_ioctl = drm_ioctl,
  #ifdef CONFIG_COMPAT
	.compat_ioctl = drm_compat_ioctl,
  #endif
        </programlisting>
      </para>
      <para>
        Drivers that implement private ioctls that requires 32/64bit
	compatibility support must provide their own
	<methodname>compat_ioctl</methodname> handler that processes private
	ioctls and calls <function>drm_compat_ioctl</function> for core ioctls.
      </para>
      <para>
        The <methodname>read</methodname> and <methodname>poll</methodname>
	operations provide support for reading DRM events and polling them. They
	are implemented by
	<programlisting>
	.poll = drm_poll,
	.read = drm_read,
	.llseek = no_llseek,
	</programlisting>
      </para>
      <para>
        The memory mapping implementation varies depending on how the driver
	manages memory. Pre-GEM drivers will use <function>drm_mmap</function>,
	while GEM-aware drivers will use <function>drm_gem_mmap</function>. See
	<xref linkend="drm-gem"/>.
	<programlisting>
	.mmap = drm_gem_mmap,
	</programlisting>
      </para>
      <para>
        No other file operation is supported by the DRM API.
      </para>
    </sect2>
    <sect2>
      <title>IOCTLs</title>
      <synopsis>struct drm_ioctl_desc *ioctls;
int num_ioctls;</synopsis>
      <abstract>Driver-specific ioctls descriptors table.</abstract>
      <para>
        Driver-specific ioctls numbers start at DRM_COMMAND_BASE. The ioctls
	descriptors table is indexed by the ioctl number offset from the base
	value. Drivers can use the DRM_IOCTL_DEF_DRV() macro to initialize the
	table entries.
      </para>
      <para>
        <programlisting>DRM_IOCTL_DEF_DRV(ioctl, func, flags)</programlisting>
	<para>
	  <parameter>ioctl</parameter> is the ioctl name. Drivers must define
	  the DRM_##ioctl and DRM_IOCTL_##ioctl macros to the ioctl number
	  offset from DRM_COMMAND_BASE and the ioctl number respectively. The
	  first macro is private to the device while the second must be exposed
	  to userspace in a public header.
	</para>
	<para>
	  <parameter>func</parameter> is a pointer to the ioctl handler function
	  compatible with the <type>drm_ioctl_t</type> type.
	  <programlisting>typedef int drm_ioctl_t(struct drm_device *dev, void *data,
		struct drm_file *file_priv);</programlisting>
	</para>
	<para>
	  <parameter>flags</parameter> is a bitmask combination of the following
	  values. It restricts how the ioctl is allowed to be called.
	  <itemizedlist>
	    <listitem><para>
	      DRM_AUTH - Only authenticated callers allowed
	    </para></listitem>
	    <listitem><para>
	      DRM_MASTER - The ioctl can only be called on the master file
	      handle
	    </para></listitem>
            <listitem><para>
	      DRM_ROOT_ONLY - Only callers with the SYSADMIN capability allowed
	    </para></listitem>
            <listitem><para>
	      DRM_CONTROL_ALLOW - The ioctl can only be called on a control
	      device
	    </para></listitem>
            <listitem><para>
	      DRM_UNLOCKED - The ioctl handler will be called without locking
	      the DRM global mutex
	    </para></listitem>
	  </itemizedlist>
	</para>
      </para>
    </sect2>
  </sect1>
  <sect1>
    <title>Legacy Support Code</title>
    <para>
      The section very briefly covers some of the old legacy support code which
      is only used by old DRM drivers which have done a so-called shadow-attach
      to the underlying device instead of registering as a real driver. This
      also includes some of the old generic buffer management and command
      submission code. Do not use any of this in new and modern drivers.
    </para>

    <sect2>
      <title>Legacy Suspend/Resume</title>
      <para>
	The DRM core provides some suspend/resume code, but drivers wanting full
	suspend/resume support should provide save() and restore() functions.
	These are called at suspend, hibernate, or resume time, and should perform
	any state save or restore required by your device across suspend or
	hibernate states.
      </para>
      <synopsis>int (*suspend) (struct drm_device *, pm_message_t state);
  int (*resume) (struct drm_device *);</synopsis>
      <para>
	Those are legacy suspend and resume methods which
	<emphasis>only</emphasis> work with the legacy shadow-attach driver
	registration functions. New driver should use the power management
	interface provided by their bus type (usually through
	the struct <structname>device_driver</structname> dev_pm_ops) and set
	these methods to NULL.
      </para>
    </sect2>

    <sect2>
      <title>Legacy DMA Services</title>
      <para>
	This should cover how DMA mapping etc. is supported by the core.
	These functions are deprecated and should not be used.
      </para>
    </sect2>
  </sect1>
  </chapter>

<!-- TODO

- Add a glossary
- Document the struct_mutex catch-all lock
- Document connector properties

- Why is the load method optional?
- What are drivers supposed to set the initial display state to, and how?
  Connector's DPMS states are not initialized and are thus equal to
  DRM_MODE_DPMS_ON. The fbcon compatibility layer calls
  drm_helper_disable_unused_functions(), which disables unused encoders and
  CRTCs, but doesn't touch the connectors' DPMS state, and
  drm_helper_connector_dpms() in reaction to fbdev blanking events. Do drivers
  that don't implement (or just don't use) fbcon compatibility need to call
  those functions themselves?
- KMS drivers must call drm_vblank_pre_modeset() and drm_vblank_post_modeset()
  around mode setting. Should this be done in the DRM core?
- vblank_disable_allowed is set to 1 in the first drm_vblank_post_modeset()
  call and never set back to 0. It seems to be safe to permanently set it to 1
  in drm_vblank_init() for KMS driver, and it might be safe for UMS drivers as
  well. This should be investigated.
- crtc and connector .save and .restore operations are only used internally in
  drivers, should they be removed from the core?
- encoder mid-layer .save and .restore operations are only used internally in
  drivers, should they be removed from the core?
- encoder mid-layer .detect operation is only used internally in drivers,
  should it be removed from the core?
-->

  <!-- External interfaces -->

  <chapter id="drmExternals">
    <title>Userland interfaces</title>
    <para>
      The DRM core exports several interfaces to applications,
      generally intended to be used through corresponding libdrm
      wrapper functions.  In addition, drivers export device-specific
      interfaces for use by userspace drivers &amp; device-aware
      applications through ioctls and sysfs files.
    </para>
    <para>
      External interfaces include: memory mapping, context management,
      DMA operations, AGP management, vblank control, fence
      management, memory management, and output management.
    </para>
    <para>
      Cover generic ioctls and sysfs layout here.  We only need high-level
      info, since man pages should cover the rest.
    </para>

  <!-- External: render nodes -->

    <sect1>
      <title>Render nodes</title>
      <para>
        DRM core provides multiple character-devices for user-space to use.
        Depending on which device is opened, user-space can perform a different
        set of operations (mainly ioctls). The primary node is always created
        and called card&lt;num&gt;. Additionally, a currently
        unused control node, called controlD&lt;num&gt; is also
        created. The primary node provides all legacy operations and
        historically was the only interface used by userspace. With KMS, the
        control node was introduced. However, the planned KMS control interface
        has never been written and so the control node stays unused to date.
      </para>
      <para>
        With the increased use of offscreen renderers and GPGPU applications,
        clients no longer require running compositors or graphics servers to
        make use of a GPU. But the DRM API required unprivileged clients to
        authenticate to a DRM-Master prior to getting GPU access. To avoid this
        step and to grant clients GPU access without authenticating, render
        nodes were introduced. Render nodes solely serve render clients, that
        is, no modesetting or privileged ioctls can be issued on render nodes.
        Only non-global rendering commands are allowed. If a driver supports
        render nodes, it must advertise it via the DRIVER_RENDER
        DRM driver capability. If not supported, the primary node must be used
        for render clients together with the legacy drmAuth authentication
        procedure.
      </para>
      <para>
        If a driver advertises render node support, DRM core will create a
        separate render node called renderD&lt;num&gt;. There will
        be one render node per device. No ioctls except  PRIME-related ioctls
        will be allowed on this node. Especially GEM_OPEN will be
        explicitly prohibited. Render nodes are designed to avoid the
        buffer-leaks, which occur if clients guess the flink names or mmap
        offsets on the legacy interface. Additionally to this basic interface,
        drivers must mark their driver-dependent render-only ioctls as
        DRM_RENDER_ALLOW so render clients can use them. Driver
        authors must be careful not to allow any privileged ioctls on render
        nodes.
      </para>
      <para>
        With render nodes, user-space can now control access to the render node
        via basic file-system access-modes. A running graphics server which
        authenticates clients on the privileged primary/legacy node is no longer
        required. Instead, a client can open the render node and is immediately
        granted GPU access. Communication between clients (or servers) is done
        via PRIME. FLINK from render node to legacy node is not supported. New
        clients must not use the insecure FLINK interface.
      </para>
      <para>
        Besides dropping all modeset/global ioctls, render nodes also drop the
        DRM-Master concept. There is no reason to associate render clients with
        a DRM-Master as they are independent of any graphics server. Besides,
        they must work without any running master, anyway.
        Drivers must be able to run without a master object if they support
        render nodes. If, on the other hand, a driver requires shared state
        between clients which is visible to user-space and accessible beyond
        open-file boundaries, they cannot support render nodes.
      </para>
    </sect1>

  <!-- External: vblank handling -->

    <sect1>
      <title>VBlank event handling</title>
      <para>
        The DRM core exposes two vertical blank related ioctls:
        <variablelist>
          <varlistentry>
            <term>DRM_IOCTL_WAIT_VBLANK</term>
            <listitem>
              <para>
                This takes a struct drm_wait_vblank structure as its argument,
                and it is used to block or request a signal when a specified
                vblank event occurs.
              </para>
            </listitem>
          </varlistentry>
          <varlistentry>
            <term>DRM_IOCTL_MODESET_CTL</term>
            <listitem>
              <para>
		This was only used for user-mode-settind drivers around
		modesetting changes to allow the kernel to update the vblank
		interrupt after mode setting, since on many devices the vertical
		blank counter is reset to 0 at some point during modeset. Modern
		drivers should not call this any more since with kernel mode
		setting it is a no-op.
              </para>
            </listitem>
          </varlistentry>
        </variablelist>
      </para>
    </sect1>

  </chapter>
</part>
<part id="drmDrivers">
  <title>DRM Drivers</title>

  <partintro>
    <para>
      This second part of the DRM Developer's Guide documents driver code,
      implementation details and also all the driver-specific userspace
      interfaces. Especially since all hardware-acceleration interfaces to
      userspace are driver specific for efficiency and other reasons these
      interfaces can be rather substantial. Hence every driver has its own
      chapter.
    </para>
  </partintro>

  <chapter id="drmI915">
    <title>drm/i915 Intel GFX Driver</title>
    <para>
      The drm/i915 driver supports all (with the exception of some very early
      models) integrated GFX chipsets with both Intel display and rendering
      blocks. This excludes a set of SoC platforms with an SGX rendering unit,
      those have basic support through the gma500 drm driver.
    </para>
    <sect1>
      <title>Display Hardware Handling</title>
      <para>
        This section covers everything related to the display hardware including
        the mode setting infrastructure, plane, sprite and cursor handling and
        display, output probing and related topics.
      </para>
      <sect2>
        <title>Mode Setting Infrastructure</title>
        <para>
          The i915 driver is thus far the only DRM driver which doesn't use the
          common DRM helper code to implement mode setting sequences. Thus it
          has its own tailor-made infrastructure for executing a display
          configuration change.
        </para>
      </sect2>
      <sect2>
        <title>Plane Configuration</title>
        <para>
	  This section covers plane configuration and composition with the
	  primary plane, sprites, cursors and overlays. This includes the
	  infrastructure to do atomic vsync'ed updates of all this state and
	  also tightly coupled topics like watermark setup and computation,
	  framebuffer compression and panel self refresh.
        </para>
      </sect2>
      <sect2>
        <title>Output Probing</title>
        <para>
	  This section covers output probing and related infrastructure like the
	  hotplug interrupt storm detection and mitigation code. Note that the
	  i915 driver still uses most of the common DRM helper code for output
	  probing, so those sections fully apply.
        </para>
      </sect2>
      <sect2>
        <title>DPIO</title>
!Pdrivers/gpu/drm/i915/i915_reg.h DPIO
	<table id="dpiox2">
	  <title>Dual channel PHY (VLV/CHV)</title>
	  <tgroup cols="8">
	    <colspec colname="c0" />
	    <colspec colname="c1" />
	    <colspec colname="c2" />
	    <colspec colname="c3" />
	    <colspec colname="c4" />
	    <colspec colname="c5" />
	    <colspec colname="c6" />
	    <colspec colname="c7" />
	    <spanspec spanname="ch0" namest="c0" nameend="c3" />
	    <spanspec spanname="ch1" namest="c4" nameend="c7" />
	    <spanspec spanname="ch0pcs01" namest="c0" nameend="c1" />
	    <spanspec spanname="ch0pcs23" namest="c2" nameend="c3" />
	    <spanspec spanname="ch1pcs01" namest="c4" nameend="c5" />
	    <spanspec spanname="ch1pcs23" namest="c6" nameend="c7" />
	    <thead>
	      <row>
		<entry spanname="ch0">CH0</entry>
		<entry spanname="ch1">CH1</entry>
	      </row>
	    </thead>
	    <tbody valign="top" align="center">
	      <row>
		<entry spanname="ch0">CMN/PLL/REF</entry>
		<entry spanname="ch1">CMN/PLL/REF</entry>
	      </row>
	      <row>
		<entry spanname="ch0pcs01">PCS01</entry>
		<entry spanname="ch0pcs23">PCS23</entry>
		<entry spanname="ch1pcs01">PCS01</entry>
		<entry spanname="ch1pcs23">PCS23</entry>
	      </row>
	      <row>
		<entry>TX0</entry>
		<entry>TX1</entry>
		<entry>TX2</entry>
		<entry>TX3</entry>
		<entry>TX0</entry>
		<entry>TX1</entry>
		<entry>TX2</entry>
		<entry>TX3</entry>
	      </row>
	      <row>
		<entry spanname="ch0">DDI0</entry>
		<entry spanname="ch1">DDI1</entry>
	      </row>
	    </tbody>
	  </tgroup>
	</table>
	<table id="dpiox1">
	  <title>Single channel PHY (CHV)</title>
	  <tgroup cols="4">
	    <colspec colname="c0" />
	    <colspec colname="c1" />
	    <colspec colname="c2" />
	    <colspec colname="c3" />
	    <spanspec spanname="ch0" namest="c0" nameend="c3" />
	    <spanspec spanname="ch0pcs01" namest="c0" nameend="c1" />
	    <spanspec spanname="ch0pcs23" namest="c2" nameend="c3" />
	    <thead>
	      <row>
		<entry spanname="ch0">CH0</entry>
	      </row>
	    </thead>
	    <tbody valign="top" align="center">
	      <row>
		<entry spanname="ch0">CMN/PLL/REF</entry>
	      </row>
	      <row>
		<entry spanname="ch0pcs01">PCS01</entry>
		<entry spanname="ch0pcs23">PCS23</entry>
	      </row>
	      <row>
		<entry>TX0</entry>
		<entry>TX1</entry>
		<entry>TX2</entry>
		<entry>TX3</entry>
	      </row>
	      <row>
		<entry spanname="ch0">DDI2</entry>
	      </row>
	    </tbody>
	  </tgroup>
	</table>
      </sect2>
    </sect1>

    <sect1>
      <title>Memory Management and Command Submission</title>
      <para>
	This sections covers all things related to the GEM implementation in the
	i915 driver.
      </para>
      <sect2>
        <title>Batchbuffer Parsing</title>
!Pdrivers/gpu/drm/i915/i915_cmd_parser.c batch buffer command parser
!Idrivers/gpu/drm/i915/i915_cmd_parser.c
      </sect2>
    </sect1>
  </chapter>
</part>
</book>