Root/Documentation/fb/tridentfb.txt

1Tridentfb is a framebuffer driver for some Trident chip based cards.
2
3The following list of chips is thought to be supported although not all are
4tested:
5
6those from the TGUI series 9440/96XX and with Cyber in their names
7those from the Image series and with Cyber in their names
8those with Blade in their names (Blade3D,CyberBlade...)
9the newer CyberBladeXP family
10
11All families are accelerated. Only PCI/AGP based cards are supported,
12none of the older Tridents.
13The driver supports 8, 16 and 32 bits per pixel depths.
14The TGUI family requires a line length to be power of 2 if acceleration
15is enabled. This means that range of possible resolutions and bpp is
16limited comparing to the range if acceleration is disabled (see list
17of parameters below).
18
19Known bugs:
201. The driver randomly locks up on 3DImage975 chip with acceleration
21   enabled. The same happens in X11 (Xorg).
222. The ramdac speeds require some more fine tuning. It is possible to
23   switch resolution which the chip does not support at some depths for
24   older chips.
25
26How to use it?
27==============
28
29When booting you can pass the video parameter.
30video=tridentfb
31
32The parameters for tridentfb are concatenated with a ':' as in this example.
33
34video=tridentfb:800x600-16@75,noaccel
35
36The second level parameters that tridentfb understands are:
37
38noaccel - turns off acceleration (when it doesn't work for your card)
39
40fp - use flat panel related stuff
41crt - assume monitor is present instead of fp
42
43center - for flat panels and resolutions smaller than native size center the
44      image, otherwise use
45stretch
46
47memsize - integer value in KB, use if your card's memory size is misdetected.
48      look at the driver output to see what it says when initializing.
49
50memdiff - integer value in KB, should be nonzero if your card reports
51      more memory than it actually has. For instance mine is 192K less than
52      detection says in all three BIOS selectable situations 2M, 4M, 8M.
53      Only use if your video memory is taken from main memory hence of
54      configurable size. Otherwise use memsize.
55      If in some modes which barely fit the memory you see garbage
56      at the bottom this might help by not letting change to that mode
57      anymore.
58
59nativex - the width in pixels of the flat panel.If you know it (usually 1024
60      800 or 1280) and it is not what the driver seems to detect use it.
61
62bpp - bits per pixel (8,16 or 32)
63mode - a mode name like 800x600-8@75 as described in
64      Documentation/fb/modedb.txt
65
66Using insane values for the above parameters will probably result in driver
67misbehaviour so take care(for instance memsize=12345678 or memdiff=23784 or
68nativex=93)
69
70Contact: jani@astechnix.ro
71

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