Not enough information to diagnose. At a guess, I would say that it was the pageflip-vs-modeset race.
** Changed in: xserver-xorg-video-intel (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to xserver-xorg-video-intel in Ubuntu. https://bugs.launchpad.net/bugs/1092269 Title: Ubuntu 12.04 hangs once, twice a day. Status in “xserver-xorg-video-intel” package in Ubuntu: Incomplete Bug description: Ubuntu 12.04 hangs once, twice a day. xdiagnose Shows error: pci0000:00: ACPI_OSC request failed (AE_ERROR), returned control mask : 0x1d Memory test shows no problem. ProblemType: Bug DistroRelease: Ubuntu 12.04 Package: xorg 1:7.6+12ubuntu1 ProcVersionSignature: Ubuntu 3.2.0-35.55-generic 3.2.34 Uname: Linux 3.2.0-35-generic x86_64 .tmp.unity.support.test.0: ApportVersion: 2.0.1-0ubuntu15.1 Architecture: amd64 CompizPlugins: [core,composite,opengl,decor,gnomecompat,imgpng,expo,place,mousepoll,ezoom,compiztoolbox,workarounds,resize,snap,wall,dbus,move,session,vpswitch,unitymtgrabhandles,grid,fade,regex,scale,unityshell] CompositorRunning: compiz Date: Wed Dec 19 14:08:23 2012 DistUpgraded: Fresh install DistroCodename: precise DistroVariant: ubuntu EcryptfsInUse: Yes GraphicsCard: Intel Corporation Ivy Bridge Graphics Controller [8086:0166] (rev 09) (prog-if 00 [VGA controller]) Subsystem: Dell Device [1028:057d] MachineType: Dell Inc. Latitude E6430s MarkForUpload: True ProcEnviron: LANGUAGE=en_CA:en TERM=xterm PATH=(custom, no user) LANG=en_CA.UTF-8 SHELL=/bin/bash ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.2.0-35-generic root=UUID=1c3277c4-f512-4f99-9c83-131ec23145ee ro quiet splash vt.handoff=7 SourcePackage: xorg UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 10/08/2012 dmi.bios.vendor: Dell Inc. dmi.bios.version: A06 dmi.board.name: 0VGXN2 dmi.board.vendor: Dell Inc. dmi.board.version: A00 dmi.chassis.type: 9 dmi.chassis.vendor: Dell Inc. dmi.modalias: dmi:bvnDellInc.:bvrA06:bd10/08/2012:svnDellInc.:pnLatitudeE6430s:pvr01:rvnDellInc.:rn0VGXN2:rvrA00:cvnDellInc.:ct9:cvr: dmi.product.name: Latitude E6430s dmi.product.version: 01 dmi.sys.vendor: Dell Inc. version.compiz: compiz 1:0.9.7.8+bzr3121-0ubuntu1 version.ia32-libs: ia32-libs N/A version.libdrm2: libdrm2 2.4.32-1ubuntu1 version.libgl1-mesa-dri: libgl1-mesa-dri 8.0.4-0ubuntu0.2 version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A version.libgl1-mesa-glx: libgl1-mesa-glx 8.0.4-0ubuntu0.2 version.xserver-xorg-core: xserver-xorg-core 2:1.11.4-0ubuntu10.8 version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.7.0-0ubuntu1.2 version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:6.14.99~git20111219.aacbd629-0ubuntu2 version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.17.0-1ubuntu4.2 version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:0.0.16+git20111201+b5534a1-1build2 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/1092269/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp