1=========
2Tridentfb
3=========
4
5Tridentfb is a framebuffer driver for some Trident chip based cards.
6
7The following list of chips is thought to be supported although not all are
8tested:
9
10those from the TGUI series 9440/96XX and with Cyber in their names
11those from the Image series and with Cyber in their names
12those with Blade in their names (Blade3D,CyberBlade...)
13the newer CyberBladeXP family
14
15All families are accelerated. Only PCI/AGP based cards are supported,
16none of the older Tridents.
17The driver supports 8, 16 and 32 bits per pixel depths.
18The TGUI family requires a line length to be power of 2 if acceleration
19is enabled. This means that range of possible resolutions and bpp is
20limited comparing to the range if acceleration is disabled (see list
21of parameters below).
22
23Known bugs:
24
251. The driver randomly locks up on 3DImage975 chip with acceleration
26   enabled. The same happens in X11 (Xorg).
272. The ramdac speeds require some more fine tuning. It is possible to
28   switch resolution which the chip does not support at some depths for
29   older chips.
30
31How to use it?
32==============
33
34When booting you can pass the video parameter::
35
36	video=tridentfb
37
38The parameters for tridentfb are concatenated with a ':' as in this example::
39
40	video=tridentfb:800x600-16@75,noaccel
41
42The second level parameters that tridentfb understands are:
43
44========  =====================================================================
45noaccel   turns off acceleration (when it doesn't work for your card)
46
47fp	  use flat panel related stuff
48crt 	  assume monitor is present instead of fp
49
50center 	  for flat panels and resolutions smaller than native size center the
51	  image, otherwise use
52stretch
53
54memsize   integer value in KB, use if your card's memory size is misdetected.
55	  look at the driver output to see what it says when initializing.
56
57memdiff   integer value in KB, should be nonzero if your card reports
58	  more memory than it actually has. For instance mine is 192K less than
59	  detection says in all three BIOS selectable situations 2M, 4M, 8M.
60	  Only use if your video memory is taken from main memory hence of
61	  configurable size. Otherwise use memsize.
62	  If in some modes which barely fit the memory you see garbage
63	  at the bottom this might help by not letting change to that mode
64	  anymore.
65
66nativex   the width in pixels of the flat panel.If you know it (usually 1024
67	  800 or 1280) and it is not what the driver seems to detect use it.
68
69bpp	  bits per pixel (8,16 or 32)
70mode	  a mode name like 800x600-8@75 as described in
71	  Documentation/fb/modedb.rst
72========  =====================================================================
73
74Using insane values for the above parameters will probably result in driver
75misbehaviour so take care(for instance memsize=12345678 or memdiff=23784 or
76nativex=93)
77
78Contact: jani@astechnix.ro
79