We should keep it open for now as it might be a genuine bug in xserver-xorg-video-i810. Can you try rebuilding it with the attached patch to see if that helps with the new kernel? Please try both versions of libgl1-mesa-dri, as I suspect this might fix the old version but regress the new one, requiring another fix for the latter.
You are right. This works with the old lib but not with new one. However it depends on the kernel version again:
Kernel 2.6.19: -old lib: works -new lib: works but prints this error message: ----- do_wait: drmWaitVBlank returned -1, IRQs don't seem to be working correctly. Try running with LIBGL_THROTTLE_REFRESH and LIBL_SYNC_REFRESH unset. ----- Kernel 2.6.20: -old lib: works -new lib: fails (error message + unusable slow)