Forwarding this bug from Ubuntu reporter Jimmyriel Vazquez:
http://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/976806

[Problem]
GPU lockup with flashing black.

[Original Description]
It started flashing and switching between the wallpaper and a black screen and it kept flashing like that. I had to do a hard reboot.

ProblemType: Crash
DistroRelease: Ubuntu 12.04
Package: xserver-xorg-video-intel 2:2.17.0-1ubuntu4
ProcVersionSignature: Ubuntu 3.2.0-22.35-generic-pae 3.2.14
Uname: Linux 3.2.0-22-generic-pae i686
.tmp.unity.support.test.0:
 
ApportVersion: 2.0-0ubuntu4
Architecture: i386
Chipset: arrandale
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: compiz
Date: Sun Apr  8 16:01:40 2012
DistUpgraded: Fresh install
DistroCodename: precise
DistroVariant: ubuntu
DuplicateSignature: [arrandale] GPU lockup  render.IPEHR: 0x02000024 Ubuntu 12.04
ExecutablePath: /usr/share/apport/apport-gpu-error-intel.py
ExtraDebuggingInterest: Yes, whatever it takes to get this fixed in Ubuntu
GpuHangFrequency: Several times a day
GpuHangReproducibility: Occurs more often under certain circumstances
GpuHangStarted: Within the last few days
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Beta i386 (20120327.1)
InterpreterPath: /usr/bin/python2.7
MachineType: Hewlett-Packard HP ProBook 4520s
ProcCmdline: /usr/bin/python /usr/share/apport/apport-gpu-error-intel.py
ProcEnviron:
 
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.2.0-22-generic-pae root=UUID=141024f5-2638-46ab-acb2-41c99202b959 ro quiet splash
SourcePackage: xserver-xorg-video-intel
Title: [arrandale] GPU lockup  render.IPEHR: 0x02000024
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups:
 
dmi.bios.date: 09/08/2011
dmi.bios.vendor: Hewlett-Packard
dmi.bios.version: 68AZZ Ver. F.20
dmi.board.name: 1413
dmi.board.vendor: Hewlett-Packard
dmi.board.version: KBC Version 57.35
dmi.chassis.type: 10
dmi.chassis.vendor: Hewlett-Packard
dmi.modalias: dmi:bvnHewlett-Packard:bvr68AZZVer.F.20:bd09/08/2011:svnHewlett-Packard:pnHPProBook4520s:pvr:rvnHewlett-Packard:rn1413:rvrKBCVersion57.35:cvnHewlett-Packard:ct10:cvr:
dmi.product.name: HP ProBook 4520s
dmi.sys.vendor: Hewlett-Packard
version.compiz: compiz 1:0.9.7.4-0ubuntu3
version.libdrm2: libdrm2 2.4.32-1ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 8.0.2-0ubuntu3
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 8.0.2-0ubuntu3
version.xserver-xorg-core: xserver-xorg-core 2:1.11.4-0ubuntu10
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.7.0-0ubuntu1
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
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:0.0.16+git20111201+b5534a1-1build2