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diff --git a/Documentation/fb/s3fb.rst b/Documentation/fb/s3fb.rst new file mode 100644 index 000000000000..e809d69c21a7 --- /dev/null +++ b/Documentation/fb/s3fb.rst @@ -0,0 +1,82 @@ +=========================================== +s3fb - fbdev driver for S3 Trio/Virge chips +=========================================== + + +Supported Hardware +================== + + S3 Trio32 + S3 Trio64 (and variants V+, UV+, V2/DX, V2/GX) + S3 Virge (and variants VX, DX, GX and GX2+) + S3 Plato/PX (completely untested) + S3 Aurora64V+ (completely untested) + + - only PCI bus supported + - only BIOS initialized VGA devices supported + - probably not working on big endian + +I tested s3fb on Trio64 (plain, V+ and V2/DX) and Virge (plain, VX, DX), +all on i386. + + +Supported Features +================== + + * 4 bpp pseudocolor modes (with 18bit palette, two variants) + * 8 bpp pseudocolor mode (with 18bit palette) + * 16 bpp truecolor modes (RGB 555 and RGB 565) + * 24 bpp truecolor mode (RGB 888) on (only on Virge VX) + * 32 bpp truecolor mode (RGB 888) on (not on Virge VX) + * text mode (activated by bpp = 0) + * interlaced mode variant (not available in text mode) + * doublescan mode variant (not available in text mode) + * panning in both directions + * suspend/resume support + * DPMS support + +Text mode is supported even in higher resolutions, but there is limitation to +lower pixclocks (maximum usually between 50-60 MHz, depending on specific +hardware, i get best results from plain S3 Trio32 card - about 75 MHz). This +limitation is not enforced by driver. Text mode supports 8bit wide fonts only +(hardware limitation) and 16bit tall fonts (driver limitation). Text mode +support is broken on S3 Trio64 V2/DX. + +There are two 4 bpp modes. First mode (selected if nonstd == 0) is mode with +packed pixels, high nibble first. Second mode (selected if nonstd == 1) is mode +with interleaved planes (1 byte interleave), MSB first. Both modes support +8bit wide fonts only (driver limitation). + +Suspend/resume works on systems that initialize video card during resume and +if device is active (for example used by fbcon). + + +Missing Features +================ +(alias TODO list) + + * secondary (not initialized by BIOS) device support + * big endian support + * Zorro bus support + * MMIO support + * 24 bpp mode support on more cards + * support for fontwidths != 8 in 4 bpp modes + * support for fontheight != 16 in text mode + * composite and external sync (is anyone able to test this?) + * hardware cursor + * video overlay support + * vsync synchronization + * feature connector support + * acceleration support (8514-like 2D, Virge 3D, busmaster transfers) + * better values for some magic registers (performance issues) + + +Known bugs +========== + + * cursor disable in text mode doesn't work + * text mode broken on S3 Trio64 V2/DX + + +-- +Ondrej Zajicek <santiago@crfreenet.org> |