Hello, I had the same problems on a 64Bit Squeeze(mostly) system. I run kernel 2.6.29 and self-compiled drm.ko and radeon.ko to get EXA acceleration with my gpu. The problems seem to have completely disappeared by upgrading xorg-server from 2:1.6.1-1 to 2:1.6.1.901-2 Best Regards, Christoph