Writing video device drivers

[Joe Foster]

Hello, all. I posted before about whether or not  device  drivers
for  the ATI VGAWonder video card existed. They don't seem to, so
I decided to write my own for Xenix 2.3.4., when  I  can  get  my
hands  on  2.3.4.  The trouble is, I don't have the foggiest idea
about where to begin. The Development System manuals  describe  a
pretty  sophisticated  interface  to the multi-screen system, but
there's no example code to get me started in the  manuals  or  on
SCO's (otherwise wonderful) new tech-support BBS.

The ATI card can emulate VGA, EGA, CGA, and  Hercules  modes,  as
well  as  adding  its  own  640x480x256  as  well  as 800x600 and
1024x768 modes in a variety of bits/pixel. I want to be  able  to
access all of the 'standard' modes as well as the super-VGA modes
through the console. I did buy ATI's technical reference  manual,
which  describes  how  to initialize the adapter for the high-rez
modes without going through the BIOS.

I would like to avoid reimplementing the 'standard' modes  in  my
driver  and  instead  pawn  support for those modes onto the CGA,
EGA, and VGA drivers already in the kernel.  I'm also thinking of
adding some new IOCTLs that would describe to programs how to use
the super-VGA modes, much like the VESA standard does in the  DOS
world.

Yes, it will be a lot of work, but seeing how I can't find a  job
for  this  summer (!%$$#%$ recession!!), I need ways to keep from
going insane from boredom!  I should still have  access  to  this
account through the summer.

Thanks for any help!

                                        Joe Foster
                                        Unemployed, un-Inc.
                                        6600joef at ucsbuxa.ucsb.edu

The opinions expressed herein are my own, and not my  employer's,
assuming I had an employer, which I don't.