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1 | |||
2 | vt8623fb - fbdev driver for graphics core in VIA VT8623 chipset | ||
3 | =============================================================== | ||
4 | |||
5 | |||
6 | Supported Hardware | ||
7 | ================== | ||
8 | |||
9 | VIA VT8623 [CLE266] chipset and its graphics core | ||
10 | (known as CastleRock or Unichrome) | ||
11 | |||
12 | I tested vt8623fb on VIA EPIA ML-6000 | ||
13 | |||
14 | |||
15 | Supported Features | ||
16 | ================== | ||
17 | |||
18 | * 4 bpp pseudocolor modes (with 18bit palette, two variants) | ||
19 | * 8 bpp pseudocolor mode (with 18bit palette) | ||
20 | * 16 bpp truecolor mode (RGB 565) | ||
21 | * 32 bpp truecolor mode (RGB 888) | ||
22 | * text mode (activated by bpp = 0) | ||
23 | * doublescan mode variant (not available in text mode) | ||
24 | * panning in both directions | ||
25 | * suspend/resume support | ||
26 | * DPMS support | ||
27 | |||
28 | Text mode is supported even in higher resolutions, but there is limitation to | ||
29 | lower pixclocks (maximum about 100 MHz). This limitation is not enforced by | ||
30 | driver. Text mode supports 8bit wide fonts only (hardware limitation) and | ||
31 | 16bit tall fonts (driver limitation). | ||
32 | |||
33 | There are two 4 bpp modes. First mode (selected if nonstd == 0) is mode with | ||
34 | packed pixels, high nibble first. Second mode (selected if nonstd == 1) is mode | ||
35 | with interleaved planes (1 byte interleave), MSB first. Both modes support | ||
36 | 8bit wide fonts only (driver limitation). | ||
37 | |||
38 | Suspend/resume works on systems that initialize video card during resume and | ||
39 | if device is active (for example used by fbcon). | ||
40 | |||
41 | |||
42 | Missing Features | ||
43 | ================ | ||
44 | (alias TODO list) | ||
45 | |||
46 | * secondary (not initialized by BIOS) device support | ||
47 | * MMIO support | ||
48 | * interlaced mode variant | ||
49 | * support for fontwidths != 8 in 4 bpp modes | ||
50 | * support for fontheight != 16 in text mode | ||
51 | * hardware cursor | ||
52 | * video overlay support | ||
53 | * vsync synchronization | ||
54 | * acceleration support (8514-like 2D, busmaster transfers) | ||
55 | |||
56 | |||
57 | Known bugs | ||
58 | ========== | ||
59 | |||
60 | * cursor disable in text mode doesn't work | ||
61 | |||
62 | |||
63 | -- | ||
64 | Ondrej Zajicek <santiago@crfreenet.org> | ||