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authorGlenn Elliott <gelliott@cs.unc.edu>2012-03-04 19:47:13 -0500
committerGlenn Elliott <gelliott@cs.unc.edu>2012-03-04 19:47:13 -0500
commitc71c03bda1e86c9d5198c5d83f712e695c4f2a1e (patch)
treeecb166cb3e2b7e2adb3b5e292245fefd23381ac8 /Documentation/fb
parentea53c912f8a86a8567697115b6a0d8152beee5c8 (diff)
parent6a00f206debf8a5c8899055726ad127dbeeed098 (diff)
Merge branch 'mpi-master' into wip-k-fmlpwip-k-fmlp
Conflicts: litmus/sched_cedf.c
Diffstat (limited to 'Documentation/fb')
-rw-r--r--Documentation/fb/00-INDEX32
-rw-r--r--Documentation/fb/sm501.txt10
-rw-r--r--Documentation/fb/udlfb.txt144
-rw-r--r--Documentation/fb/viafb.txt48
4 files changed, 227 insertions, 7 deletions
diff --git a/Documentation/fb/00-INDEX b/Documentation/fb/00-INDEX
index a618fd99c9f0..30a70542e823 100644
--- a/Documentation/fb/00-INDEX
+++ b/Documentation/fb/00-INDEX
@@ -4,33 +4,41 @@ please mail me.
4 Geert Uytterhoeven <geert@linux-m68k.org> 4 Geert Uytterhoeven <geert@linux-m68k.org>
5 5
600-INDEX 600-INDEX
7 - this file 7 - this file.
8arkfb.txt 8arkfb.txt
9 - info on the fbdev driver for ARK Logic chips. 9 - info on the fbdev driver for ARK Logic chips.
10aty128fb.txt 10aty128fb.txt
11 - info on the ATI Rage128 frame buffer driver. 11 - info on the ATI Rage128 frame buffer driver.
12cirrusfb.txt 12cirrusfb.txt
13 - info on the driver for Cirrus Logic chipsets. 13 - info on the driver for Cirrus Logic chipsets.
14cmap_xfbdev.txt
15 - an introduction to fbdev's cmap structures.
14deferred_io.txt 16deferred_io.txt
15 - an introduction to deferred IO. 17 - an introduction to deferred IO.
18efifb.txt
19 - info on the EFI platform driver for Intel based Apple computers.
20ep93xx-fb.txt
21 - info on the driver for EP93xx LCD controller.
16fbcon.txt 22fbcon.txt
17 - intro to and usage guide for the framebuffer console (fbcon). 23 - intro to and usage guide for the framebuffer console (fbcon).
18framebuffer.txt 24framebuffer.txt
19 - introduction to frame buffer devices. 25 - introduction to frame buffer devices.
20imacfb.txt 26gxfb.txt
21 - info on the generic EFI platform driver for Intel based Macs. 27 - info on the framebuffer driver for AMD Geode GX2 based processors.
22intel810.txt 28intel810.txt
23 - documentation for the Intel 810/815 framebuffer driver. 29 - documentation for the Intel 810/815 framebuffer driver.
24intelfb.txt 30intelfb.txt
25 - docs for Intel 830M/845G/852GM/855GM/865G/915G/945G fb driver. 31 - docs for Intel 830M/845G/852GM/855GM/865G/915G/945G fb driver.
26internals.txt 32internals.txt
27 - quick overview of frame buffer device internals. 33 - quick overview of frame buffer device internals.
34lxfb.txt
35 - info on the framebuffer driver for AMD Geode LX based processors.
28matroxfb.txt 36matroxfb.txt
29 - info on the Matrox framebuffer driver for Alpha, Intel and PPC. 37 - info on the Matrox framebuffer driver for Alpha, Intel and PPC.
38metronomefb.txt
39 - info on the driver for the Metronome display controller.
30modedb.txt 40modedb.txt
31 - info on the video mode database. 41 - info on the video mode database.
32matroxfb.txt
33 - info on the Matrox frame buffer driver.
34pvr2fb.txt 42pvr2fb.txt
35 - info on the PowerVR 2 frame buffer driver. 43 - info on the PowerVR 2 frame buffer driver.
36pxafb.txt 44pxafb.txt
@@ -39,13 +47,23 @@ s3fb.txt
39 - info on the fbdev driver for S3 Trio/Virge chips. 47 - info on the fbdev driver for S3 Trio/Virge chips.
40sa1100fb.txt 48sa1100fb.txt
41 - information about the driver for the SA-1100 LCD controller. 49 - information about the driver for the SA-1100 LCD controller.
50sh7760fb.txt
51 - info on the SH7760/SH7763 integrated LCDC Framebuffer driver.
42sisfb.txt 52sisfb.txt
43 - info on the framebuffer device driver for various SiS chips. 53 - info on the framebuffer device driver for various SiS chips.
44sstfb.txt 54sstfb.txt
45 - info on the frame buffer driver for 3dfx' Voodoo Graphics boards. 55 - info on the frame buffer driver for 3dfx' Voodoo Graphics boards.
46tgafb.txt 56tgafb.txt
47 - info on the TGA (DECChip 21030) frame buffer driver 57 - info on the TGA (DECChip 21030) frame buffer driver.
58tridentfb.txt
59 info on the framebuffer driver for some Trident chip based cards.
60uvesafb.txt
61 - info on the userspace VESA (VBE2+ compliant) frame buffer device.
48vesafb.txt 62vesafb.txt
49 - info on the VESA frame buffer device 63 - info on the VESA frame buffer device.
64viafb.modes
65 - list of modes for VIA Integration Graphic Chip.
66viafb.txt
67 - info on the VIA Integration Graphic Chip console framebuffer driver.
50vt8623fb.txt 68vt8623fb.txt
51 - info on the fb driver for the graphics core in VIA VT8623 chipsets. 69 - info on the fb driver for the graphics core in VIA VT8623 chipsets.
diff --git a/Documentation/fb/sm501.txt b/Documentation/fb/sm501.txt
new file mode 100644
index 000000000000..8d17aebd2648
--- /dev/null
+++ b/Documentation/fb/sm501.txt
@@ -0,0 +1,10 @@
1Configuration:
2
3You can pass the following kernel command line options to sm501 videoframebuffer:
4
5 sm501fb.bpp= SM501 Display driver:
6 Specifiy bits-per-pixel if not specified by 'mode'
7
8 sm501fb.mode= SM501 Display driver:
9 Specify resolution as
10 "<xres>x<yres>[-<bpp>][@<refresh>]"
diff --git a/Documentation/fb/udlfb.txt b/Documentation/fb/udlfb.txt
new file mode 100644
index 000000000000..7fdde2a02a27
--- /dev/null
+++ b/Documentation/fb/udlfb.txt
@@ -0,0 +1,144 @@
1
2What is udlfb?
3===============
4
5This is a driver for DisplayLink USB 2.0 era graphics chips.
6
7DisplayLink chips provide simple hline/blit operations with some compression,
8pairing that with a hardware framebuffer (16MB) on the other end of the
9USB wire. That hardware framebuffer is able to drive the VGA, DVI, or HDMI
10monitor with no CPU involvement until a pixel has to change.
11
12The CPU or other local resource does all the rendering; optinally compares the
13result with a local shadow of the remote hardware framebuffer to identify
14the minimal set of pixels that have changed; and compresses and sends those
15pixels line-by-line via USB bulk transfers.
16
17Because of the efficiency of bulk transfers and a protocol on top that
18does not require any acks - the effect is very low latency that
19can support surprisingly high resolutions with good performance for
20non-gaming and non-video applications.
21
22Mode setting, EDID read, etc are other bulk or control transfers. Mode
23setting is very flexible - able to set nearly arbitrary modes from any timing.
24
25Advantages of USB graphics in general:
26
27 * Ability to add a nearly arbitrary number of displays to any USB 2.0
28 capable system. On Linux, number of displays is limited by fbdev interface
29 (FB_MAX is currently 32). Of course, all USB devices on the same
30 host controller share the same 480Mbs USB 2.0 interface.
31
32Advantages of supporting DisplayLink chips with kernel framebuffer interface:
33
34 * The actual hardware functionality of DisplayLink chips matches nearly
35 one-to-one with the fbdev interface, making the driver quite small and
36 tight relative to the functionality it provides.
37 * X servers and other applications can use the standard fbdev interface
38 from user mode to talk to the device, without needing to know anything
39 about USB or DisplayLink's protocol at all. A "displaylink" X driver
40 and a slightly modified "fbdev" X driver are among those that already do.
41
42Disadvantages:
43
44 * Fbdev's mmap interface assumes a real hardware framebuffer is mapped.
45 In the case of USB graphics, it is just an allocated (virtual) buffer.
46 Writes need to be detected and encoded into USB bulk transfers by the CPU.
47 Accurate damage/changed area notifications work around this problem.
48 In the future, hopefully fbdev will be enhanced with an small standard
49 interface to allow mmap clients to report damage, for the benefit
50 of virtual or remote framebuffers.
51 * Fbdev does not arbitrate client ownership of the framebuffer well.
52 * Fbcon assumes the first framebuffer it finds should be consumed for console.
53 * It's not clear what the future of fbdev is, given the rise of KMS/DRM.
54
55How to use it?
56==============
57
58Udlfb, when loaded as a module, will match against all USB 2.0 generation
59DisplayLink chips (Alex and Ollie family). It will then attempt to read the EDID
60of the monitor, and set the best common mode between the DisplayLink device
61and the monitor's capabilities.
62
63If the DisplayLink device is successful, it will paint a "green screen" which
64means that from a hardware and fbdev software perspective, everything is good.
65
66At that point, a /dev/fb? interface will be present for user-mode applications
67to open and begin writing to the framebuffer of the DisplayLink device using
68standard fbdev calls. Note that if mmap() is used, by default the user mode
69application must send down damage notifcations to trigger repaints of the
70changed regions. Alternatively, udlfb can be recompiled with experimental
71defio support enabled, to support a page-fault based detection mechanism
72that can work without explicit notifcation.
73
74The most common client of udlfb is xf86-video-displaylink or a modified
75xf86-video-fbdev X server. These servers have no real DisplayLink specific
76code. They write to the standard framebuffer interface and rely on udlfb
77to do its thing. The one extra feature they have is the ability to report
78rectangles from the X DAMAGE protocol extension down to udlfb via udlfb's
79damage interface (which will hopefully be standardized for all virtual
80framebuffers that need damage info). These damage notifications allow
81udlfb to efficiently process the changed pixels.
82
83Module Options
84==============
85
86Special configuration for udlfb is usually unnecessary. There are a few
87options, however.
88
89From the command line, pass options to modprobe
90modprobe udlfb defio=1 console=1
91
92Or for permanent option, create file like /etc/modprobe.d/options with text
93options udlfb defio=1 console=1
94
95Accepted options:
96
97fb_defio Make use of the fb_defio (CONFIG_FB_DEFERRED_IO) kernel
98 module to track changed areas of the framebuffer by page faults.
99 Standard fbdev applications that use mmap but that do not
100 report damage, may be able to work with this enabled.
101 Disabled by default because of overhead and other issues.
102
103console Allow fbcon to attach to udlfb provided framebuffers. This
104 is disabled by default because fbcon will aggressively consume
105 the first framebuffer it finds, which isn't usually what the
106 user wants in the case of USB displays.
107
108Sysfs Attributes
109================
110
111Udlfb creates several files in /sys/class/graphics/fb?
112Where ? is the sequential framebuffer id of the particular DisplayLink device
113
114edid If a valid EDID blob is written to this file (typically
115 by a udev rule), then udlfb will use this EDID as a
116 backup in case reading the actual EDID of the monitor
117 attached to the DisplayLink device fails. This is
118 especially useful for fixed panels, etc. that cannot
119 communicate their capabilities via EDID. Reading
120 this file returns the current EDID of the attached
121 monitor (or last backup value written). This is
122 useful to get the EDID of the attached monitor,
123 which can be passed to utilities like parse-edid.
124
125metrics_bytes_rendered 32-bit count of pixel bytes rendered
126
127metrics_bytes_identical 32-bit count of how many of those bytes were found to be
128 unchanged, based on a shadow framebuffer check
129
130metrics_bytes_sent 32-bit count of how many bytes were transferred over
131 USB to communicate the resulting changed pixels to the
132 hardware. Includes compression and protocol overhead
133
134metrics_cpu_kcycles_used 32-bit count of CPU cycles used in processing the
135 above pixels (in thousands of cycles).
136
137metrics_reset Write-only. Any write to this file resets all metrics
138 above to zero. Note that the 32-bit counters above
139 roll over very quickly. To get reliable results, design
140 performance tests to start and finish in a very short
141 period of time (one minute or less is safe).
142
143--
144Bernie Thompson <bernie@plugable.com>
diff --git a/Documentation/fb/viafb.txt b/Documentation/fb/viafb.txt
index f3e046a6a987..444e34b52ae1 100644
--- a/Documentation/fb/viafb.txt
+++ b/Documentation/fb/viafb.txt
@@ -197,6 +197,54 @@ Notes:
197 example, 197 example,
198 # fbset -depth 16 198 # fbset -depth 16
199 199
200
201[Configure viafb via /proc]
202---------------------------
203 The following files exist in /proc/viafb
204
205 supported_output_devices
206
207 This read-only file contains a full ',' separated list containing all
208 output devices that could be available on your platform. It is likely
209 that not all of those have a connector on your hardware but it should
210 provide a good starting point to figure out which of those names match
211 a real connector.
212 Example:
213 # cat /proc/viafb/supported_output_devices
214
215 iga1/output_devices
216 iga2/output_devices
217
218 These two files are readable and writable. iga1 and iga2 are the two
219 independent units that produce the screen image. Those images can be
220 forwarded to one or more output devices. Reading those files is a way
221 to query which output devices are currently used by an iga.
222 Example:
223 # cat /proc/viafb/iga1/output_devices
224 If there are no output devices printed the output of this iga is lost.
225 This can happen for example if only one (the other) iga is used.
226 Writing to these files allows adjusting the output devices during
227 runtime. One can add new devices, remove existing ones or switch
228 between igas. Essentially you can write a ',' separated list of device
229 names (or a single one) in the same format as the output to those
230 files. You can add a '+' or '-' as a prefix allowing simple addition
231 and removal of devices. So a prefix '+' adds the devices from your list
232 to the already existing ones, '-' removes the listed devices from the
233 existing ones and if no prefix is given it replaces all existing ones
234 with the listed ones. If you remove devices they are expected to turn
235 off. If you add devices that are already part of the other iga they are
236 removed there and added to the new one.
237 Examples:
238 Add CRT as output device to iga1
239 # echo +CRT > /proc/viafb/iga1/output_devices
240
241 Remove (turn off) DVP1 and LVDS1 as output devices of iga2
242 # echo -DVP1,LVDS1 > /proc/viafb/iga2/output_devices
243
244 Replace all iga1 output devices by CRT
245 # echo CRT > /proc/viafb/iga1/output_devices
246
247
200[Bootup with viafb]: 248[Bootup with viafb]:
201-------------------- 249--------------------
202 Add the following line to your grub.conf: 250 Add the following line to your grub.conf: