Comment 13 for bug 545039

@Guilherme:

This appears to be the stack trace where the issue arises:

 1) | drm_ioctl() {
 1) 0.421 us | drm_ut_debug_printk();
 1) | i915_gem_set_domain_ioctl() {
 1) 0.624 us | drm_gem_object_lookup();
 1) 0.504 us | intel_mark_busy();
 1) | i915_gem_object_set_to_gtt_domain() {
 1) 0.456 us | i915_gem_object_flush_gpu_write_domain();
 1) | i915_gem_object_wait_rendering() {
 1) | i915_do_wait_request() {
 1) 2.018 us | i915_user_irq_get();

At this point it would be helpful if we could confirm this as being present in the latest mainline kernel or not. If it is, we will need to open a bug against the i915 driver to get this resolved as it's beyond my ability to figure out what is going wrong here. The issue seems to be a real software-hardware interaction issue and not a pure software bug.

Please download and test the latest mainline kernel from http://kernel.ubuntu.com/~kernel-ppa/mainline/.

Thanks