xref: /openbmc/linux/Documentation/fb/tgafb.rst (revision 2cf1c348)
1==============
2What is tgafb?
3==============
4
5This is a driver for DECChip 21030 based graphics framebuffers, a.k.a. TGA
6cards, which are usually found in older Digital Alpha systems. The
7following models are supported:
8
9- ZLxP-E1 (8bpp, 2 MB VRAM)
10- ZLxP-E2 (32bpp, 8 MB VRAM)
11- ZLxP-E3 (32bpp, 16 MB VRAM, Zbuffer)
12
13This version is an almost complete rewrite of the code written by Geert
14Uytterhoeven, which was based on the original TGA console code written by
15Jay Estabrook.
16
17Major new features since Linux 2.0.x:
18
19 * Support for multiple resolutions
20 * Support for fixed-frequency and other oddball monitors
21   (by allowing the video mode to be set at boot time)
22
23User-visible changes since Linux 2.2.x:
24
25 * Sync-on-green is now handled properly
26 * More useful information is printed on bootup
27   (this helps if people run into problems)
28
29This driver does not (yet) support the TGA2 family of framebuffers, so the
30PowerStorm 3D30/4D20 (also known as PBXGB) cards are not supported. These
31can however be used with the standard VGA Text Console driver.
32
33
34Configuration
35=============
36
37You can pass kernel command line options to tgafb with
38`video=tgafb:option1,option2:value2,option3` (multiple options should be
39separated by comma, values are separated from options by `:`).
40
41Accepted options:
42
43==========  ============================================================
44font:X      default font to use. All fonts are supported, including the
45	    SUN12x22 font which is very nice at high resolutions.
46
47mode:X      default video mode. The following video modes are supported:
48	    640x480-60, 800x600-56, 640x480-72, 800x600-60, 800x600-72,
49	    1024x768-60, 1152x864-60, 1024x768-70, 1024x768-76,
50	    1152x864-70, 1280x1024-61, 1024x768-85, 1280x1024-70,
51	    1152x864-84, 1280x1024-76, 1280x1024-85
52==========  ============================================================
53
54
55Known Issues
56============
57
58The XFree86 FBDev server has been reported not to work, since tgafb doesn't do
59mmap(). Running the standard XF86_TGA server from XFree86 3.3.x works fine for
60me, however this server does not do acceleration, which make certain operations
61quite slow. Support for acceleration is being progressively integrated in
62XFree86 4.x.
63
64When running tgafb in resolutions higher than 640x480, on switching VCs from
65tgafb to XF86_TGA 3.3.x, the entire screen is not re-drawn and must be manually
66refreshed. This is an X server problem, not a tgafb problem, and is fixed in
67XFree86 4.0.
68
69Enjoy!
70
71Martin Lucina <mato@kotelna.sk>
72