Bug 22624

Using intel driver 6.8.0+git20090201.d394e0b8-2 as currently packaged by Ubuntu Karmic, and kernel 2.6.31 from same distro, I see a 100% reliable deadlock.  With compiz enabled, after the screen fades to black due to idle timeout, I get this in dmesg:

[  600.840070] INFO: task events/1:10 blocked for more than 120 seconds.
[  600.840078] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[  600.840085] events/1      D 0000000000000000     0    10      2 0x00000000
[  600.840096]  ffff88007b3c3d70 0000000000000046 ffff88007b3c3dd0 0000000000015540
[  600.840107]  ffff88007b3c83b0 0000000000015540 0000000000015540 0000000000015540
[  600.840117]  0000000000015540 ffff88007b3c83b0 0000000000015540 0000000000015540
[  600.840127] Call Trace:
[  600.840145]  [<ffffffff81512c07>] __mutex_lock_slowpath+0xd7/0x160
[  600.840154]  [<ffffffff81512b06>] mutex_lock+0x26/0x50
[  600.840195]  [<ffffffffa005f538>] i915_gem_retire_work_handler+0x38/0x90 [i915]
[  600.840221]  [<ffffffffa005f500>] ? i915_gem_retire_work_handler+0x0/0x90 [i915]
[  600.840233]  [<ffffffff8106bb15>] run_workqueue+0x95/0x170
[  600.840240]  [<ffffffff8106bc94>] worker_thread+0xa4/0x120
[  600.840250]  [<ffffffff81070e10>] ? autoremove_wake_function+0x0/0x40
[  600.840258]  [<ffffffff8106bbf0>] ? worker_thread+0x0/0x120
[  600.840266]  [<ffffffff81070a26>] kthread+0x96/0xa0
[  600.840275]  [<ffffffff8101308a>] child_rip+0xa/0x20
[  600.840284]  [<ffffffff81070990>] ? kthread+0x0/0xa0
[  600.840291]  [<ffffffff81013080>] ? child_rip+0x0/0x20
[  600.840322] INFO: task Xorg:2550 blocked for more than 120 seconds.
[  600.840326] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[  600.840331] Xorg          D 0000000000000000     0  2550   2549 0x00400004
[  600.840341]  ffff880072cb1cb8 0000000000000086 fffffff57a1be000 0000000000015540
[  600.840351]  ffff880078e6b110 0000000000015540 0000000000015540 0000000000015540
[  600.840361]  0000000000015540 ffff880078e6b110 0000000000015540 0000000000015540
[  600.840370] Call Trace:
[  600.840380]  [<ffffffff81512c07>] __mutex_lock_slowpath+0xd7/0x160
[  600.840390]  [<ffffffff8140c949>] ? sock_aio_read+0x149/0x150
[  600.840398]  [<ffffffff81512b06>] mutex_lock+0x26/0x50
[  600.840423]  [<ffffffffa005f816>] i915_gem_throttle_ioctl+0x36/0x90 [i915]
[  600.840460]  [<ffffffffa0026c6e>] drm_ioctl+0x17e/0x3a0 [drm]
[  600.840471]  [<ffffffff81114d32>] ? do_sync_read+0xf2/0x130
[  600.840481]  [<ffffffff81070e10>] ? autoremove_wake_function+0x0/0x40
[  600.840491]  [<ffffffff810313f9>] ? default_spin_lock_flags+0x9/0x10
[  600.840499]  [<ffffffff81513eca>] ? _spin_lock_irqsave+0x2a/0x40
[  600.840508]  [<ffffffff81123f5c>] vfs_ioctl+0x7c/0xa0
[  600.840516]  [<ffffffff81124529>] do_vfs_ioctl+0x79/0x370
[  600.840523]  [<ffffffff811248a1>] sys_ioctl+0x81/0xa0
[  600.840533]  [<ffffffff81011fc2>] system_call_fastpath+0x16/0x1b

The display is totally hung.  No keystroke can turn the display back on, chvt hangs, all X clients hang.  However the machine itself continues to work fine, aside from the display.

My machine has a 00:02.0 VGA compatible controller: Intel Corporation Mobile GM965/GL960 Integrated Graphics Controller (rev 0c) and I don't have a xorg.conf i.e. I'm using all defaults.  Xorg.log attached.