Comment 0 for bug 966399

During QA testing of 11.10 on unreleased Ivybridge systems, we have encountered quite a few GPU hang bugs in mesa that take out the desktop that have been fixed in the stable mesa-7.11 branch after 11.10 released. Given that 7.11.2 is quite large and different than 7.11.0 that is in oneiric, I've backported just the fixes for the issues we have found.

These include:

GPU reset loop leading to a hard hang of the system when these apps are run on Ivybridge: qgears2, openarena, unigine heaven, trine, minecraft
Hard hang of the system when these apps are run on Sandybridge: trine, oilrush
Wrong colors rendered in lightsmark on Ivybridge

To verify, install phoronix test suite on an Ivybridge system, and run the qgears2 benchmark

TEST CASE:
1. log in to desktop on an Ivybridge system
2. install phoronix-test-suite (sudo apt-get install phoronix-test-suite)
3. run lightsmark or qgears2 test (phoronix-test suite run lightsmark)

If it fails, dmesg will be flooded with these errors and the desktop will be unusable

Jan 26 12:44:41 u kernel: [ 4260.408090] [drm:i915_hangcheck_elapsed] *ERROR* Hangcheck timer elapsed... GPU hung
Jan 26 12:44:41 u kernel: [ 4260.408104] [drm] capturing error event; look for more information in /debug/dri/0/i915_error_state
Jan 26 12:44:41 u kernel: [ 4260.414015] [drm:i915_wait_request] *ERROR* i915_wait_request returns -11 (awaiting 1332092 at 1332083, next 1332093)
Jan 26 12:44:47 u kernel: [ 4266.772122] [drm:i915_hangcheck_elapsed] *ERROR* Hangcheck timer elapsed... GPU hung
Jan 26 12:48:11 u kernel: [ 4470.536612] qgears[27719]: segfault at 0 ip 01d36611 sp bfd950c0 error 4 in i965_dri.so[1cc2000+bc000]