xref: /openbmc/linux/Documentation/fb/aty128fb.rst (revision aac28965)
1=================
2What is aty128fb?
3=================
4
5.. [This file is cloned from VesaFB/matroxfb]
6
7This is a driver for a graphic framebuffer for ATI Rage128 based devices
8on Intel and PPC boxes.
9
10Advantages:
11
12 * It provides a nice large console (128 cols + 48 lines with 1024x768)
13   without using tiny, unreadable fonts.
14 * You can run XF68_FBDev on top of /dev/fb0
15 * Most important: boot logo :-)
16
17Disadvantages:
18
19 * graphic mode is slower than text mode... but you should not notice
20   if you use same resolution as you used in textmode.
21 * still experimental.
22
23
24How to use it?
25==============
26
27Switching modes is done using the  video=aty128fb:<resolution>... modedb
28boot parameter or using `fbset` program.
29
30See Documentation/fb/modedb.rst for more information on modedb
31resolutions.
32
33You should compile in both vgacon (to boot if you remove your Rage128 from
34box) and aty128fb (for graphics mode). You should not compile-in vesafb
35unless you have primary display on non-Rage128 VBE2.0 device (see
36Documentation/fb/vesafb.rst for details).
37
38
39X11
40===
41
42XF68_FBDev should generally work fine, but it is non-accelerated. As of
43this document, 8 and 32bpp works fine.  There have been palette issues
44when switching from X to console and back to X.  You will have to restart
45X to fix this.
46
47
48Configuration
49=============
50
51You can pass kernel command line options to vesafb with
52`video=aty128fb:option1,option2:value2,option3` (multiple options should
53be separated by comma, values are separated from options by `:`).
54Accepted options:
55
56========= =======================================================
57noaccel   do not use acceleration engine. It is default.
58accel     use acceleration engine. Not finished.
59vmode:x   chooses PowerMacintosh video mode <x>. Deprecated.
60cmode:x   chooses PowerMacintosh colour mode <x>. Deprecated.
61<XxX@X>   selects startup videomode. See modedb.txt for detailed
62	  explanation. Default is 640x480x8bpp.
63========= =======================================================
64
65
66Limitations
67===========
68
69There are known and unknown bugs, features and misfeatures.
70Currently there are following known bugs:
71
72 - This driver is still experimental and is not finished.  Too many
73   bugs/errata to list here.
74
75Brad Douglas <brad@neruo.com>
76