A few days ago I bought a cheap ATI Radeon AGP graphics card to try and extend the life of my desktop system.
The first bug I encountered was that the OpenGL compositing in KDE4
wasn't stable. I added some extra bits to the xorg.conf
config file that is supposed to help (it didn't seem to on it's own)
and I told KDE4's kwin that it wasn't to do a compositing
compatibility test, it should just do it. With that all in place,
OpenGL worked and everything was fine and dandy.
Yesterday I upgraded my Debian "squeeze" system and AMD/ATI's fglrx
driver was upgraded to version 10-6-1 from 10-5-1. When I restarted
X it crashed horribly. Apparently this is a known bug in Xorg and
you just need to make sure you have BusID "PCI:1:0:0"
(or whatever) set correctly in your xorg.conf file.
Today I diligently updated my xorg.conf file and restarted
X and it worked. However now all KDE4 windows are blank and I can't use
them, so I've gone back to the open-source radeonhd driver until I
can figure out what I need to tweak next to fix it.
Not that I'm complaining, I am running Debian testing and I am playing with fire in using the AMD/ATI official drivers, which are noted for the unreliability...