Package: xserver-xorg-video-radeon Version: 1:6.13.1-2+squeeze1 On my mac mini 1.33 + squeeze the same error appears. I checked the gdb stack and it was very similar to the one posted. The line causing segfault was line 224: pVidMode->Next = pVidMode->First->next; It would be great if this could be solved. Zoltan