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diff --git a/Documentation/fb/tgafb.rst b/Documentation/fb/tgafb.rst new file mode 100644 index 000000000..0c50d2134 --- /dev/null +++ b/Documentation/fb/tgafb.rst @@ -0,0 +1,71 @@ +============== +What is tgafb? +============== + +This is a driver for DECChip 21030 based graphics framebuffers, a.k.a. TGA +cards, which are usually found in older Digital Alpha systems. The +following models are supported: + +- ZLxP-E1 (8bpp, 2 MB VRAM) +- ZLxP-E2 (32bpp, 8 MB VRAM) +- ZLxP-E3 (32bpp, 16 MB VRAM, Zbuffer) + +This version is an almost complete rewrite of the code written by Geert +Uytterhoeven, which was based on the original TGA console code written by +Jay Estabrook. + +Major new features since Linux 2.0.x: + + * Support for multiple resolutions + * Support for fixed-frequency and other oddball monitors + (by allowing the video mode to be set at boot time) + +User-visible changes since Linux 2.2.x: + + * Sync-on-green is now handled properly + * More useful information is printed on bootup + (this helps if people run into problems) + +This driver does not (yet) support the TGA2 family of framebuffers, so the +PowerStorm 3D30/4D20 (also known as PBXGB) cards are not supported. These +can however be used with the standard VGA Text Console driver. + + +Configuration +============= + +You can pass kernel command line options to tgafb with +`video=tgafb:option1,option2:value2,option3` (multiple options should be +separated by comma, values are separated from options by `:`). + +Accepted options: + +========== ============================================================ +font:X default font to use. All fonts are supported, including the + SUN12x22 font which is very nice at high resolutions. + +mode:X default video mode. The following video modes are supported: + 640x480-60, 800x600-56, 640x480-72, 800x600-60, 800x600-72, + 1024x768-60, 1152x864-60, 1024x768-70, 1024x768-76, + 1152x864-70, 1280x1024-61, 1024x768-85, 1280x1024-70, + 1152x864-84, 1280x1024-76, 1280x1024-85 +========== ============================================================ + + +Known Issues +============ + +The XFree86 FBDev server has been reported not to work, since tgafb doesn't do +mmap(). Running the standard XF86_TGA server from XFree86 3.3.x works fine for +me, however this server does not do acceleration, which make certain operations +quite slow. Support for acceleration is being progressively integrated in +XFree86 4.x. + +When running tgafb in resolutions higher than 640x480, on switching VCs from +tgafb to XF86_TGA 3.3.x, the entire screen is not re-drawn and must be manually +refreshed. This is an X server problem, not a tgafb problem, and is fixed in +XFree86 4.0. + +Enjoy! + +Martin Lucina <mato@kotelna.sk> |