xref: /openbmc/linux/Documentation/fb/pvr2fb.rst (revision a44e4f3a)
1===============
2What is pvr2fb?
3===============
4
5This is a driver for PowerVR 2 based graphics frame buffers, such as the
6one found in the Dreamcast.
7
8Advantages:
9
10 * It provides a nice large console (128 cols + 48 lines with 1024x768)
11   without using tiny, unreadable fonts (NOT on the Dreamcast)
12 * You can run XF86_FBDev on top of /dev/fb0
13 * Most important: boot logo :-)
14
15Disadvantages:
16
17 * Driver is largely untested on non-Dreamcast systems.
18
19Configuration
20=============
21
22You can pass kernel command line options to pvr2fb with
23`video=pvr2fb:option1,option2:value2,option3` (multiple options should be
24separated by comma, values are separated from options by `:`).
25
26Accepted options:
27
28==========  ==================================================================
29font:X      default font to use. All fonts are supported, including the
30	    SUN12x22 font which is very nice at high resolutions.
31
32
33mode:X      default video mode with format [xres]x[yres]-<bpp>@<refresh rate>
34	    The following video modes are supported:
35	    640x640-16@60, 640x480-24@60, 640x480-32@60. The Dreamcast
36	    defaults to 640x480-16@60. At the time of writing the
37	    24bpp and 32bpp modes function poorly. Work to fix that is
38	    ongoing
39
40	    Note: the 640x240 mode is currently broken, and should not be
41	    used for any reason. It is only mentioned here as a reference.
42
43inverse     invert colors on screen (for LCD displays)
44
45nomtrr      disables write combining on frame buffer. This slows down driver
46	    but there is reported minor incompatibility between GUS DMA and
47	    XFree under high loads if write combining is enabled (sound
48	    dropouts). MTRR is enabled by default on systems that have it
49	    configured and that support it.
50
51cable:X     cable type. This can be any of the following: vga, rgb, and
52	    composite. If none is specified, we guess.
53
54output:X    output type. This can be any of the following: pal, ntsc, and
55	    vga. If none is specified, we guess.
56==========  ==================================================================
57
58X11
59===
60
61XF86_FBDev has been shown to work on the Dreamcast in the past - though not yet
62on any 2.6 series kernel.
63
64Paul Mundt <lethal@linuxdc.org>
65
66Updated by Adrian McMenamin <adrian@mcmen.demon.co.uk>
67