Subversion Repositories or1k

Introduction

          This is a frame buffer device driver for 3dfx' Voodoo Graphics 
        video boards. It's highly experimental code, but is guaranteed to work
        and with me "between chair and keyboard". Some people tested other
        combinations and it seems that it works.
          The main page is located at <http://sstfb.sourceforge.net>, and if
        you want the latest version, check out the CVS, as the driver is a work
        in progress, I feel incomfortable with releasing tarballs of something
        not completely working...Don't worry, it's still more than useable
        (I eat my own dog food)

          Please read the Bug section, and report any success or failure to me
        (Ghozlane Toumi <gtoumi@laposte.net>).
          BTW, If you have only one monitor , and you don't feel like playing
        with the vga passthrou cable, I can only suggest borrowing a screen
        somewhere... 


Installation 

          This driver (should) work on ix86, with "late" 2.2.x kernel (tested
        with x = 19) and "recent" 2.4.x kernel, as a module or compiled in.
          It has been included in mainstream kernel since the infamous 2.4.10.
          You can apply the patches found in sstfb/kernel/*-2.{2|4}.x.patch,
        and copy sstfb.c to linux/drivers/video/, or apply a single patch, 
        sstfb/patch-2.{2|4}.x-sstfb-yymmdd to your linux source tree.

          Then configure your kernel as usual: choose "m" or "y" to 3Dfx Voodoo
        Graphics in section "console". Compile, install, have fun... and please
        drop me a report :)


Module Usage
        
        Warnings.
        # You should read completely this section before issuing any command.
        # If you have only one monitor to play with, once you insmod the
          module, the 3dfx takes control of the output, so you'll have to
          plug the monitor to the "normal" video board in order to issue
          the commands, or you can blindly use sst_dbg_vgapass
          in the tools directory (See Tools). The latest solution is pass the
          parameter vgapass=1 when insmodding the driver. (See Kernel/Modules
          Options)

        Module insertion:
        # insmod sstfb.o
          you should see some strange output frome the board: 
          a big blue square, a green and a red small squares and a vertical
          white rectangle. why ? the function's name is self explanatory :
          "sstfb_test()"...
          (if you don't have a second monitor, you'll have to plug your monitor
          directely to the 2D videocard to see what you're typing)
        # con2fb /dev/fbx /dev/ttyx
          bind a tty to the new frame buffer. if you already have a frame
          buffer driver, the voodoo fb will likely be /dev/fb1. if not, 
          the device will be /dev/fb0. You can check this by doing a 
          cat /proc/fb. You can find a copy of con2fb in tools/ directory.
          if you don't have another fb device, this step is superfluous,
          as the console subsystem automagicaly binds ttys to the fb.
        # switch to the virtual console you just mapped. "tadaaa" ...

        Module removal:
        # con2fb /dev/fbx /dev/ttyx
          bind the tty to the old frame buffer so the module can be removed.
          (how does it work with vgacon ? short answer : it doesn't work)
        # rmmod sstfb


Kernel/Modules Options

        You can pass some otions to sstfb module, and via the kernel command
        line when the driver is compiled in :
        for module : insmod sstfb.o option1=value1 option2=value2 ...
        in kernel :  video=sstfb:option1,option2:value2,option3 ...
        
        sstfb supports the folowing options :

Module          Kernel          Description

vgapass=0       vganopass       Enable or disable VGA passthrou cable.
vgapass=1       vgapass         When enabled, the monitor will get the signal
                                from the VGA board and not from the voodoo.
                                Default: nopass

mem=x           mem:x           Force frame buffer memory in MiB
                                allowed values: 0, 1, 2, 4.
                                Default: 0 (= autodetect)

inverse=1       inverse         Supposed to enable inverse console.
                                doesn't work yet...

clipping=1      clipping        Enable or disable clipping.
clipping=0      noclipping      With clipping enabled, all offscreen
                                reads and writes are disgarded.
                                Default: enable clipping.

gfxclk=x        gfxclk:x        Force graphic clock frequency (in MHz).
                                Be carefull with this option, it may be
                                DANGEROUS.
                                Default: auto 
                                        50Mhz for Voodoo 1,
                                        75MHz for Voodoo 2. 

slowpci=1       fastpci         Enable or disable fast PCI read/writes.
slowpci=1       slowpci         Default : fastpci

dev=x           dev:x           Attach the driver to device number x.
                                0 is the first compatible board (in 
                                lspci order)

Tools

        These tools are mostly for debugging purposes, but you can 
        find some of these interesting :
         - con2fb , maps a tty to a fbramebuffer .
                con2fb /dev/fb1 /dev/tty5
         - sst_dbg_vgapass , changes vga passthrou. You have to recompile the
        driver with SST_DEBUG and SST_DEBUG_IOCTL set to 1
                sst_dbg_vgapass /dev/fb1 1 (enables vga cable)
                sst_dbg_vgapass /dev/fb1 0 (disables vga cable)
         - glide_reset , resets the voodoo using glide
                use this after rmmoding sstfb, if the module refuses to
                reinsert .

Bugs

        - DO NOT use glide while the sstfb module is in, you'll most likely
        hang your computer.
        - If you see some artefacts (pixels not cleaning and stuff like that), 
        try turning off clipping (clipping=0), and/or using slowpci
        - the driver don't detect the 4Mb frame buffer voodoos, it seems that
        the 2 last Mbs wrap around. looking into that .
        - The driver is 16 bpp only, 24/32 won't work.
        - The driver is not your_favorite_toy-safe. this includes SMP...
          [Actually from inspection it seems to be safe - Alan]
        - when using XFree86 FBdev (X over fbdev) you may see strange color
        patterns at the border of your windows (the pixels loose the lowest
        byte -> basicaly the blue component nd some of the green) . I'm unable
        to reproduce this with XFree86-3.3, but one of the testers has this
        problem with XFree86-4. apparently recent Xfree86-4.x solve this
        problem.
        - I didn't really test changing the palette, so you may find some weird
        things when playing with that.
        - Sometimes the driver will not recognise the DAC , and the
        initialisation will fail. this is specificaly true for
        voodoo 2 boards , but it should be solved in recent versions. please
        contact me .
        - the 24/32 is not likely to work anytime soon , knowing that the
        hardware does ... unusual thigs in 24/32 bpp
        - When used with anther video board, current limitations of linux
        console subsystem can cause some troubles, specificaly, you should
        disable software scrollback , as it can oops badly ...

Todo

        - Get rid of the previous paragraph.
        - Buy more coffee.
        - test/port to other arch.
        - try to add panning using tweeks with front and back buffer .
        - try to implement accel on voodoo2 , this board can actualy do a 
          lot in 2D even if it was sold as a 3D only board ...

ghoz.

-- 
Ghozlane Toumi <gtoumi@laposte.net>


$Date: 2004-04-15 02:32:00 $
http://sstfb.sourceforge.net/README