This reliably happens to me when dragging a firefox window from one monitor to another in 13.04. As above, unity --replace fails and I have to reboot the computer to make it work again. It seems to have started just a week or two ago.
Hardware/software info: Dell Latitude E6410 00:02.0 VGA compatible controller [0300]: Intel Corporation Core Processor Integrated Graphics Controller [8086:0046] (rev 02) ii libgl1-mesa-dri:amd64 9.1.7-1ubuntu2 amd64 free implementation of the OpenGL API -- DRI modules ii xserver-xorg-video-intel 2:2.21.6-0ubuntu4.3 amd64 X.Org X server -- Intel i8xx, i9xx display driver In dmesg, I see: [ 280.763186] [drm:i915_hangcheck_hung] *ERROR* Hangcheck timer elapsed... GPU hung [ 280.763195] [drm] capturing error event; look for more information in /debug/dri/0/i915_error_state [ 282.750114] [drm:i915_hangcheck_hung] *ERROR* Hangcheck timer elapsed... GPU hung [ 282.750272] [drm:i915_reset] *ERROR* GPU hanging too fast, declaring wedged! [ 282.750275] [drm:i915_reset] *ERROR* Failed to reset chip. I'm not sure how to see /debug/dri/0/i915_error_state - is there a /debug filesystem I can mount or something? -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to mesa in Ubuntu. https://bugs.launchpad.net/bugs/932900 Title: Unity freeze, crashes when trying to restart - GPU lockup with IPEHR: 0x7a000002 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/mesa/+bug/932900/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp