Ok i managed to get drm and opengl working on this system but its not very stable yet. I still have my X server crashing or freezing under heavy load.
I followed the exact procedure as documented on a pdf at viaarena using ubuntu 7.04.
Be warned this document has some holes and oversights its not exactly a step by step some stuff was just plain wrong so untill i resolve the stability issue i would rather not post any specific processes i changed as they are probably also wrong
However if you follow that procedure you should be able to get stuff working.
A few things not on that doc are as follows.
I had to modify my xorg.conf
Identifier "VIA Technologies, Inc. S3 Unichrome Pro VGA Adapter"
Option "DisableIRQ" "true"
Option "EnableAGPDMA" "false"
Option "NoXVDMA" "true"
Also the Driver "via" is actually "unichrome" i think but i just renambed the custom driver i compiled per the doc to via_drv.so so it works as shown.