I was wrong, DebugWait didn't help. I disabled DebugWait again of course. It looks as if upgrading to kernel v3.19-rc1 did though.
I got the kernel here: http://kernel.ubuntu.com/~kernel- ppa/mainline/v3.19-rc1-vivid/ However, the commit ID of the patch doesn't match the one Daniel Vetter gave above. I found this though, with the same commit description: https://github.com/torvalds/linux/commit/656bfa3afc14e45e2d9e1624bf60d79b3beb12f2 In debugfs, I can see that the new code paths are getting hit: # cat /sys/kernel/debug/dri/0/i915_swizzle_info bit6 swizzle for X-tiling = bit9/bit10/bit11 bit6 swizzle for Y-tiling = bit9/bit11 DDC = 0x000f0002 DDC2 = 0x00000000 C0DRB3 = 0x0000 C1DRB3 = 0x0000 L-shaped memory detected -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1393205 Title: Intel q35 bug on Ubuntu 14.04 (Screen Artifacts) To manage notifications about this bug go to: https://bugs.launchpad.net/xserver-xorg-video-intel/+bug/1393205/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
