Comment 19 for bug 476817

I'm running into a similar problem with Karmic and the 855GM chipset. I'll try some of the suggested fixes and report more detailed debugging output later. I started having the problem upon upgrading to Karmic. When the freeze occurs, it's when an OpenGL application, like a screensaver, starts up, though only sometimes. One way to reproduce the problem is by running this from the shell:

  while [ 1 ]; do date; /usr/lib/xscreensaver/biof & sleep 5; pkill biof; sleep 1; done

Usually this will cause a freeze in ten or twenty iterations. At this point I ssh into my laptop and reboot. When I check kern.log, I see something like this shortly after the time of the freeze:

Jan 9 23:31:02 OUTOPIA kernel: [ 720.432931] INFO: task biof:2570 blocked for more than 120 seconds.
Jan 9 23:31:02 OUTOPIA kernel: [ 720.432938] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
Jan 9 23:31:02 OUTOPIA kernel: [ 720.432946] biof D c08145c0 0 2570 2482 0x00000004
Jan 9 23:31:02 OUTOPIA kernel: [ 720.432958] ebb61db4 00000086 eb9ce000 c08145c0 eb9f9bb8 c08145c0 1fad12dc 0000007f
Jan 9 23:31:02 OUTOPIA kernel: [ 720.432979] c08145c0 c08145c0 eb9f9bb8 c08145c0 00000000 0000007f c08145c0 db08f000
Jan 9 23:31:02 OUTOPIA kernel: [ 720.432998] eb9f9920 f68ebc14 f68ebc18 ffffffff ebb61de0 c056fc86 c031120e f68ebc1c
Jan 9 23:31:02 OUTOPIA kernel: [ 720.433018] Call Trace:
Jan 9 23:31:02 OUTOPIA kernel: [ 720.433030] [<c056fc86>] __mutex_lock_slowpath+0xc6/0x130
Jan 9 23:31:02 OUTOPIA kernel: [ 720.433043] [<c031120e>] ? get_from_free_list+0x3e/0x50
Jan 9 23:31:02 OUTOPIA kernel: [ 720.433054] [<c056fba0>] mutex_lock+0x20/0x40
Jan 9 23:31:02 OUTOPIA kernel: [ 720.433097] [<f8224b77>] i915_gem_gtt_pwrite_fast+0x47/0x150 [i915]
Jan 9 23:31:02 OUTOPIA kernel: [ 720.433150] [<f81ad68b>] ? drm_gem_object_lookup+0x3b/0x50 [drm]
Jan 9 23:31:02 OUTOPIA kernel: [ 720.433195] [<f822672a>] i915_gem_pwrite_ioctl+0x1aa/0x1d0 [i915]
Jan 9 23:31:02 OUTOPIA kernel: [ 720.433208] [<c015f193>] ? hrtimer_forward+0x163/0x1b0
Jan 9 23:31:02 OUTOPIA kernel: [ 720.433262] [<f81ac6c0>] drm_ioctl+0x180/0x360 [drm]
Jan 9 23:31:02 OUTOPIA kernel: [ 720.433308] [<f8226580>] ? i915_gem_pwrite_ioctl+0x0/0x1d0 [i915]
Jan 9 23:31:02 OUTOPIA kernel: [ 720.433321] [<c0150146>] ? run_timer_softirq+0x156/0x200
Jan 9 23:31:02 OUTOPIA kernel: [ 720.433337] [<c013387d>] ? __enqueue_entity+0x9d/0xc0
Jan 9 23:31:02 OUTOPIA kernel: [ 720.433349] [<c0133231>] ? __dequeue_entity+0x21/0x40
Jan 9 23:31:02 OUTOPIA kernel: [ 720.433367] [<c01f51f3>] vfs_ioctl+0x73/0x90
Jan 9 23:31:02 OUTOPIA kernel: [ 720.433379] [<c01f54c1>] do_vfs_ioctl+0x71/0x310
Jan 9 23:31:02 OUTOPIA kernel: [ 720.433390] [<c01f57bf>] sys_ioctl+0x5f/0x80
Jan 9 23:31:02 OUTOPIA kernel: [ 720.433401] [<c010336c>] syscall_call+0x7/0xb

More to follow.