Do you have the following section in /etc/X11/xorg.conf?
Code:
Section "DRI"
Mode 0666
EndSection
You also need to make sure that bus mastering is enabled in the BIOS. To check this, run the following command as root:
Code:
setpci -s 00:01.0 4.w
The last character has to be 4-7 or C-F. If not, then it needs to be enabled.
One more thing, I don't know if it's required any more with the newest X server but you may need to specify a larger amount of reserve RAM for video processing - try adding the following line to the graphics "Device" section of xorg.conf:
The number may need to be increased, so if that doesn't work try bumping it up to 16384.
