The crash seems to happen in drm_intel_gem_bo_start_gtt_access(),
judging from those stacktraces.

2010/7/14 Martin Vielsmaier <email address hidden>:
> When the system is frozen it is enough to kill compiz to break the freeze.
> I attached gdb to compiz while frozen, here is the stack:
> (gdb) info stack
> #0  0x00007fc45b2d2187 in ioctl () from /lib/libc.so.6
> #1  0x00007fc45891e84d in drm_intel_gem_bo_start_gtt_access () from /lib/libdrm_intel.so.1
> #2  0x00007fc458d8d70f in ?? () from /usr/lib/dri/i965_dri.so
> #3  0x00007fc45ba3d612 in glXSwapBuffers () from /usr/lib/mesa/libGL.so.1
> #4  0x0000000000413302 in eventLoop ()
> #5  0x000000000040d8e9 in main ()
>
> A second time with some more debug symbols installed:
> (gdb) info stack
> #0  0x00007f2c27198187 in ioctl () from /lib/libc.so.6
> #1  0x00007f2c247e484d in drm_intel_gem_bo_start_gtt_access (bo=0x1ac6960, write_enable=<value optimized out>)
>    at ../../intel/intel_bufmgr_gem.c:1145
> #2  0x00007f2c24c5370f in ?? () from /usr/lib/dri/i965_dri.so
> #3  0x00007f2c27903116 in ?? () from /usr/lib/mesa/libGL.so.1
> #4  0x0000000000412afb in eventLoop ()
> #5  0x000000000040d8e9 in main ()
>
> I also believe that this problem is closely linked to OpenGL activity. Before I touch the brightness keys everything is fine. Compiz and glxgears run. When I touched the brightness keys (sometimes I need to touch them more than one time), compiz freezes. When I kill it via a SSH session and then start glxgears it freezes too.
> Attached gdb to frozen glxgears, stack:
> (gdb) info stack
> #0  0x00007ff3a3abf187 in ioctl () from /lib/libc.so.6
> #1  0x00007ff3a1c6c84d in drm_intel_gem_bo_start_gtt_access () from /lib/libdrm_intel.so.1
> #2  0x00007ff3a20db70f in ?? () from /usr/lib/dri/i965_dri.so
> #3  0x00007ff3a4560612 in glXSwapBuffers () from /usr/lib/mesa/libGL.so.1
> #4  0x000000000040339f in ?? ()
> #5  0x00007ff3a39ffc4d in __libc_start_main () from /lib/libc.so.6
> #6  0x00000000004018c9 in ?? ()
> #7  0x00007fff1b7b1d78 in ?? ()
> #8  0x000000000000001c in ?? ()
> #9  0x0000000000000001 in ?? ()
> #10 0x00007fff1b7b3645 in ?? ()
> #11 0x0000000000000000 in ?? ()
>
> Second time:
> (gdb) info stack
> #0  0x00007f0027c5d187 in ioctl () from /lib/libc.so.6
> #1  0x00007f0025e0a84d in drm_intel_gem_bo_start_gtt_access (bo=0x25f8be0, write_enable=<value optimized out>)
>    at ../../intel/intel_bufmgr_gem.c:1145
> #2  0x00007f002627970f in ?? () from /usr/lib/dri/i965_dri.so
> #3  0x00007f00286fe612 in glXSwapBuffers () from /usr/lib/mesa/libGL.so.1
> #4  0x000000000040339f in ?? ()
> #5  0x00007f0027b9dc4d in __libc_start_main () from /lib/libc.so.6
> #6  0x00000000004018c9 in ?? ()
> #7  0x00007ffff7897138 in ?? ()
> #8  0x000000000000001c in ?? ()
> #9  0x0000000000000001 in ?? ()
> #10 0x00007ffff7897680 in ?? ()
> #11 0x0000000000000000 in ?? ()
>
> Any ideas what could trigger the bug? (Note that when the brightness
> keys were touched once, this bug persists. So I think that some register
> on the graphics card is set wrong and from then on causes problems... Is
> there a way to read them all at once to see what changes?)
>
> --
> [gm45] Adjusting Brightness in Acer Aspire Timelines causes system freeze in 4810T and 5810T models
> https://bugs.launchpad.net/bugs/446717
> You received this bug notification because you are a direct subscriber
> of a duplicate bug.
>