Created attachment 28391 [details] dmesg output with GPU hung messages Following my report on https://bugzilla.kernel.org/show_bug.cgi?id=15671, the bug still exists in 2.6.35.4 but is much less frequent, which could be due to my kernel configuration (selecting some kernels options would increase the occurrence of this bug). I see that in this 2.6.35.4 release an extra debug message seems to have been added "[drm:init_ring_common] *ERROR* render ring head not reset to zero ctl 00000000 head 02001000 tail 00000000 start 02001000 [drm:init_ring_common] *ERROR* render ring head forced to zero ctl 00000000 head 00000000 tail 00000000 start 02001000". Please check the attached dmesg output for the full output. After that I need to go to a console and "reboot", cause the screen stops updating on X.
A bug in the userspace driver. Can you please attach Xorg.log and /sys/kernel/debug/dri/0/i915_error_state? [Might be best moved to bugs.freedesktop.org as well where it is more likely to get the attention of the appropriate developers.]
The render ring reset error message has been resolved. The GPU hang is due to a userspace driver bug, for which an i915_error_state is required to help debugging.