xref: /openbmc/linux/Documentation/fb/lxfb.rst (revision 6c33a6f4)
1=============
2What is lxfb?
3=============
4
5.. [This file is cloned from VesaFB/aty128fb]
6
7
8This is a graphics framebuffer driver for AMD Geode LX based processors.
9
10Advantages:
11
12 * No need to use AMD's VSA code (or other VESA emulation layer) in the
13   BIOS.
14 * It provides a nice large console (128 cols + 48 lines with 1024x768)
15   without using tiny, unreadable fonts.
16 * You can run XF68_FBDev on top of /dev/fb0
17 * Most important: boot logo :-)
18
19Disadvantages:
20
21 * graphic mode is slower than text mode...
22
23
24How to use it?
25==============
26
27Switching modes is done using  lxfb.mode_option=<resolution>... boot
28parameter or using `fbset` program.
29
30See Documentation/fb/modedb.rst for more information on modedb
31resolutions.
32
33
34X11
35===
36
37XF68_FBDev should generally work fine, but it is non-accelerated.
38
39
40Configuration
41=============
42
43You can pass kernel command line options to lxfb with lxfb.<option>.
44For example, lxfb.mode_option=800x600@75.
45Accepted options:
46
47================ ==================================================
48mode_option	 specify the video mode.  Of the form
49		 <x>x<y>[-<bpp>][@<refresh>]
50vram		 size of video ram (normally auto-detected)
51vt_switch	 enable vt switching during suspend/resume.  The vt
52		 switch is slow, but harmless.
53================ ==================================================
54
55Andres Salomon <dilinger@debian.org>
56