Comment 99 for bug 745608

I've just done an Ubuntu 11.04 install and tested with different kernels and I find 2.6.33 is OK, 2.6.34 is a problem. The bisection between .33 and .34 is as follows:

# bad: [e40152ee1e1c7a63f4777791863215e3faa37a86] Linus 2.6.34
# good: [60b341b778cc2929df16c0a504c91621b3c6a4ad] Linux 2.6.33
git bisect start 'v2.6.34' 'v2.6.33' '--' 'drivers/gpu/drm/i915/'
# good: [ae3db24aab398fb5f985696c12362eb12ef65812] drm/i915: extract fence stealing code
git bisect good ae3db24aab398fb5f985696c12362eb12ef65812
# bad: [8956c8bba5b11b3d3aec000e6c6184943011a8d4] drm/i915: Set up the documented clock gating on Sandybridge and Ironlake.
git bisect bad 8956c8bba5b11b3d3aec000e6c6184943011a8d4
# good: [1c62233508ef7104f8a78e571fdf5c72d0dc0200] Merge branch 'gpu-switcher' of /ssd/git//linux-2.6 into drm-next-stage
git bisect good 1c62233508ef7104f8a78e571fdf5c72d0dc0200
# bad: [71cf39b117d5aa817a4693f4478397e6b04bee25] drm/i915: Enable VS timer dispatch.
git bisect bad 71cf39b117d5aa817a4693f4478397e6b04bee25
# bad: [5d9391628e8eb3b0830697697a95bfd0c3c35b9e] drm/i915: remove an unnecessary wait_request()
git bisect bad 5d9391628e8eb3b0830697697a95bfd0c3c35b9e
# bad: [f05dd2f09cac422c423dae8f9b8e2be13df05a8f] drm/i915: Don't bother with the BKL for GEM ioctls.
git bisect bad f05dd2f09cac422c423dae8f9b8e2be13df05a8f

This is the same result as comment #8. Further, putting

Section "Device"
 Identifier "Intel 915GM"
 Driver "intel"
 Option "Tiling" "false"
EndSection

in /etc/X11/xorg.conf doesn't stop the problem from occurring.