1
2Introduction
3
4	  This is a frame buffer device driver for 3dfx' Voodoo Graphics 
5	(aka voodoo 1, aka sst1) and Voodoo² (aka Voodoo 2, aka CVG) based 
6	video boards. It's highly experimental code, but is guaranteed to work
7	on my computer, with my "Maxi Gamer 3D" and "Maxi Gamer 3d²" boards,
8	and with me "between chair and keyboard". Some people tested other
9	combinations and it seems that it works.
10	  The main page is located at <http://sstfb.sourceforge.net>, and if
11	you want the latest version, check out the CVS, as the driver is a work
12	in progress, I feel uncomfortable with releasing tarballs of something
13	not completely working...Don't worry, it's still more than usable
14	(I eat my own dog food)
15
16	  Please read the Bug section, and report any success or failure to me
17	(Ghozlane Toumi <gtoumi@laposte.net>).
18	  BTW, If you have only one monitor , and you don't feel like playing
19	with the vga passthrou cable, I can only suggest borrowing a screen
20	somewhere... 
21
22
23Installation 
24
25	  This driver (should) work on ix86, with "late" 2.2.x kernel (tested
26	with x = 19) and "recent" 2.4.x kernel, as a module or compiled in.
27	  It has been included in mainstream kernel since the infamous 2.4.10.
28	  You can apply the patches found in sstfb/kernel/*-2.{2|4}.x.patch,
29	and copy sstfb.c to linux/drivers/video/, or apply a single patch, 
30	sstfb/patch-2.{2|4}.x-sstfb-yymmdd to your linux source tree.
31
32	  Then configure your kernel as usual: choose "m" or "y" to 3Dfx Voodoo
33	Graphics in section "console". Compile, install, have fun... and please
34	drop me a report :)
35
36
37Module Usage
38	
39	Warnings.
40	# You should read completely this section before issuing any command.
41	# If you have only one monitor to play with, once you insmod the
42	  module, the 3dfx takes control of the output, so you'll have to
43	  plug the monitor to the "normal" video board in order to issue
44	  the commands, or you can blindly use sst_dbg_vgapass
45          in the tools directory (See Tools). The latest solution is pass the
46	  parameter vgapass=1 when insmodding the driver. (See Kernel/Modules
47	  Options)
48
49	Module insertion:
50	# insmod sstfb.o
51	  you should see some strange output from the board: 
52	  a big blue square, a green and a red small squares and a vertical
53	  white rectangle. why? the function's name is self-explanatory:
54	  "sstfb_test()"...
55	  (if you don't have a second monitor, you'll have to plug your monitor
56	  directly to the 2D videocard to see what you're typing)
57	# con2fb /dev/fbx /dev/ttyx
58	  bind a tty to the new frame buffer. if you already have a frame
59	  buffer driver, the voodoo fb will likely be /dev/fb1. if not, 
60	  the device will be /dev/fb0. You can check this by doing a 
61	  cat /proc/fb. You can find a copy of con2fb in tools/ directory.
62	  if you don't have another fb device, this step is superfluous,
63	  as the console subsystem automagicaly binds ttys to the fb.
64	# switch to the virtual console you just mapped. "tadaaa" ...
65
66	Module removal:
67	# con2fb /dev/fbx /dev/ttyx
68	  bind the tty to the old frame buffer so the module can be removed.
69	  (how does it work with vgacon ? short answer : it doesn't work)
70	# rmmod sstfb
71
72
73Kernel/Modules Options
74
75	You can pass some options to the sstfb module, and via the kernel 
76	command line when the driver is compiled in:
77	for module : insmod sstfb.o option1=value1 option2=value2 ...
78	in kernel :  video=sstfb:option1,option2:value2,option3 ...
79	
80	sstfb supports the following options :
81
82Module		Kernel		Description
83
84vgapass=0	vganopass	Enable or disable VGA passthrou cable.
85vgapass=1	vgapass		When enabled, the monitor will get the signal
86				from the VGA board and not from the voodoo.
87				Default: nopass
88
89mem=x		mem:x		Force frame buffer memory in MiB
90				allowed values: 0, 1, 2, 4.
91				Default: 0 (= autodetect)
92
93inverse=1	inverse		Supposed to enable inverse console.
94				doesn't work yet...
95
96clipping=1	clipping	Enable or disable clipping.
97clipping=0	noclipping	With clipping enabled, all offscreen
98				reads and writes are discarded.
99				Default: enable clipping.
100
101gfxclk=x	gfxclk:x	Force graphic clock frequency (in MHz).
102				Be careful with this option, it may be
103				DANGEROUS.
104				Default: auto 
105					50Mhz for Voodoo 1,
106					75MHz for Voodoo 2. 
107
108slowpci=1	fastpci		Enable or disable fast PCI read/writes.
109slowpci=1	slowpci		Default : fastpci
110
111dev=x		dev:x		Attach the driver to device number x.
112				0 is the first compatible board (in 
113				lspci order)
114
115Tools
116
117	These tools are mostly for debugging purposes, but you can 
118	find some of these interesting :
119	 - con2fb , maps a tty to a fbramebuffer .
120		con2fb /dev/fb1 /dev/tty5
121	 - sst_dbg_vgapass , changes vga passthrou. You have to recompile the
122	driver with SST_DEBUG and SST_DEBUG_IOCTL set to 1
123		sst_dbg_vgapass /dev/fb1 1 (enables vga cable)
124		sst_dbg_vgapass /dev/fb1 0 (disables vga cable)
125	 - glide_reset , resets the voodoo using glide
126		use this after rmmoding sstfb, if the module refuses to
127		reinsert .
128
129Bugs
130
131	- DO NOT use glide while the sstfb module is in, you'll most likely
132	hang your computer.
133	- If you see some artefacts (pixels not cleaning and stuff like that), 
134	try turning off clipping (clipping=0), and/or using slowpci
135	- the driver don't detect the 4Mb frame buffer voodoos, it seems that
136	the 2 last Mbs wrap around. looking into that .
137	- The driver is 16 bpp only, 24/32 won't work.
138	- The driver is not your_favorite_toy-safe. this includes SMP...
139          [Actually from inspection it seems to be safe - Alan]
140	- When using XFree86 FBdev (X over fbdev) you may see strange color
141	patterns at the border of your windows (the pixels lose the lowest
142	byte -> basically the blue component and some of the green). I'm unable
143	to reproduce this with XFree86-3.3, but one of the testers has this
144	problem with XFree86-4. Apparently recent Xfree86-4.x solve this
145	problem.
146	- I didn't really test changing the palette, so you may find some weird
147	things when playing with that.
148	- Sometimes the driver will not recognise the DAC, and the
149        initialisation will fail. This is specifically true for
150	voodoo 2 boards, but it should be solved in recent versions. Please
151	contact me.
152	- The 24/32 is not likely to work anytime soon, knowing that the
153	hardware does ... unusual things in 24/32 bpp.
154	- When used with another video board, current limitations of the linux
155	console subsystem can cause some troubles, specifically, you should
156	disable software scrollback, as it can oops badly ...
157
158Todo
159
160	- Get rid of the previous paragraph.
161	- Buy more coffee.
162	- test/port to other arch.
163	- try to add panning using tweeks with front and back buffer .
164	- try to implement accel on voodoo2, this board can actually do a 
165	  lot in 2D even if it was sold as a 3D only board ...
166
167ghoz.
168
169-- 
170Ghozlane Toumi <gtoumi@laposte.net>
171
172
173$Date: 2002/05/09 20:11:45 $
174http://sstfb.sourceforge.net/README
175