Created attachment 63097 [details] dmesg I have experienced 4 hangs of the kernel from http://kernel.ubuntu.com/~kernel-ppa/mainline/drm-intel-experimental/2012-06-15-quantal/ One was during boot, when splash screen should be displayed. Three others when I tied to launch x server startx /usr/bin/ck-launch-session xterm In three cases only power off button helped. I could not switch to console, magic SysRq keys did not work. The screen was blank. Once the problem was not so severe and my script (launched with timeout) was able to catch logs. Dmesg: [ 587.488223] [drm:intel_update_fbc], fbc disabled per module param [ 588.087685] BUG: unable to handle kernel NULL pointer dereference at 00000010 [ 588.087783] IP: [<f896baed>] i915_switch_context+0x5d/0xe0 [i915] [ 588.087838] *pdpt = 000000003472c001 *pde = 0000000000000000 [ 588.087890] Oops: 0000 [#1] SMP i915_error_state and Xorg.0.log do not contain errors. Usually "apport" put his file in /var/crash, but now there is no fresh dumps. So the other crashes were due to kernel hangs. I do not see the problem with older kernels, e.g. drm-intel-experimental/2012-06-13 lspci 00:02.0 VGA compatible controller: Intel Corporation Mobile GM965/GL960 Integrated Graphics Controller (primary) (rev 03) 00:02.1 Display controller: Intel Corporation Mobile GM965/GL960 Integrated Graphics Controller (secondary) (rev 03) ASUS F80L laptop uname -i i386 Ubuntu 12.04 + xorgs-edgers ppa + drm-intel-experimental kernel xserver-xorg-video-intel Version: 2:2.19.0+git20120613.0db789e1-0ubuntu0sarvatt~precise xserver-xorg-core Version: 2:1.12.2+git20120605+server-1.12-branch.aaf48906-0ubuntu0ricotz~precise libgl1-mesa-dri Version: 8.1~git20120529.f92b2e5e-0ubuntu0sarvatt~precise libdrm-intel1 Version: 2.4.35+git20120613.d1fcfb17-0ubuntu0sarvatt~precise
Created attachment 63116 [details] [review] Disable contexts when HW doesn't support it. Please give this patch a shot.
The problem is that I have no idea where the sources of http://kernel.ubuntu.com/~kernel-ppa/mainline/drm-intel-experimental/ kernels reside. I can not associate these kernels neither with ubuntu git repositories nor with people.freedesktop.org/~danvet/drm-intel or another repository at freedesktop.
With drm-intel-experimental/2012-06-17-quantal/ even [Alt+SysRq+b] does not help.
I've pushed the fix here for you to try. You'll need to work with #ubuntu, or build your own kernel to test it. I'd really like to know your result, it does fix an issue I see on my ILK, so I suspect this to be the problem. http://cgit.freedesktop.org/~bwidawsk/drm-intel/log/?h=for-max
Fix is merged to drm-intel-next-queued (which is the branch the drm-intel-experimental ppa kernel is built from): commit e158c5aa1776372cd751e2c395300a3a6ff0bc9c Author: Ben Widawsky <ben@bwidawsk.net> Date: Sun Jun 17 09:37:24 2012 -0700 drm/i915: disable contexts on old HW Thanks for reporintg this bug, please reopen if you still have issues.
I have checked the problem is apparent in commit 8e96d9c4d9843f00ebeb4a9b33596d96602ea101 Author: Ben Widawsky Date: Mon Jun 4 14:42:56 2012 -0700 drm/i915: reset the GPU on context fini but I can not reproduce it with the following commit commit 9a70e1d4e200333d39b1e8407cbcbdaf515b33d8 Author: Ben Widawsky Date: Sat Jun 16 05:21:13 2012 -0700 drm/i915: disable contexts on old HW Thank you for the fix.
Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.