hangcheck occure.

$ lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 12.04.3 LTS
Release:	12.04
Codename:	precise

$ grep \(EE\) Xorg.0.log
[ 52302.812] (EE) intel(0): Detected a hung GPU, disabling acceleration.
[ 52302.812] (EE) intel(0): When reporting this, please include i915_error_state from debugfs and the full dmesg.

$ dmesg | tail
[39859.567501] ath9k 0000:02:00.0 wlan0: disabling VHT as WMM/QoS is not supported by the AP
[39859.568516] wlan0: associate with 00:0d:02:4e:e2:68 (try 1/3)
[39859.571139] wlan0: RX AssocResp from 00:0d:02:4e:e2:68 (capab=0x431 status=0 aid=1)
[39859.571390] wlan0: associated
[39859.571399] IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
[49786.700884] CPUM: APIC 01 at 00000000fee00000 (mapped at ffffc90000676000) - ver 0x01060015, lint0=0x10700 lint1=0x10400 pc=0x00400 thmr=0x000fa
[49786.700897] CPUM: APIC 00 at 00000000fee00000 (mapped at ffffc9000067e000) - ver 0x01060015, lint0=0x10700 lint1=0x00400 pc=0x10400 thmr=0x000fa
[52239.562498] [drm:i915_hangcheck_hung] *ERROR* Hangcheck timer elapsed... GPU hung
[52239.562504] [drm] capturing error event; look for more information in /debug/dri/0/i915_error_state
[52247.552940] [drm:i915_hangcheck_hung] *ERROR* Hangcheck timer elapsed... GPU hung

$ uname -a
Linux 26897LJ 3.8.0-31-generic #46~precise1-Ubuntu SMP Wed Sep 11 18:21:16 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux

$ sudo hwinfo --short
cpu:
                       Intel(R) Celeron(R) CPU B820 @ 1.70GHz, 800 MHz
                       Intel(R) Celeron(R) CPU B820 @ 1.70GHz, 800 MHz
keyboard:
  /dev/input/event3    AT Translated Set 2 keyboard
mouse:
  /dev/input/mice      Microsoft ® Laser Mouse 6000
  /dev/input/mice      SynPS/2 Synaptics TouchPad
graphics card:
                       Intel VGA compatible controller
sound:
                       Intel Audio device
storage:
                       Intel SATA controller
network:
  wlan0                Atheros WLAN controller
  eth0                 Attansic Ethernet controller
network interface:
  wlan0                WLAN network interface
  eth0                 Ethernet network interface
  lo                   Loopback network interface
disk:
  /dev/sda             ST320LT020-9YG14
  /dev/sdb             Multiple Card  Reader
partition:
  /dev/sda1            Partition
  /dev/sda2            Partition
  /dev/sda3            Partition
  /dev/sda4            Partition
cdrom:
  /dev/sr0             MATSHITA DVD-RAM UJ8C1
usb controller:
                       Intel USB Controller
                       Intel USB Controller
                       Intel USB Controller
bios:
                       BIOS
bridge:
                       Intel Host bridge
                       Intel PCI bridge
                       Intel PCI bridge
                       Intel PCI bridge
                       Intel ISA bridge
hub:
                       Linux 3.8.0-31-generic xhci_hcd xHCI Host Controller
                       Linux 3.8.0-31-generic xhci_hcd xHCI Host Controller
                       Linux 3.8.0-31-generic ehci_hcd EHCI Host Controller
                       Hub
                       Linux 3.8.0-31-generic ehci_hcd EHCI Host Controller
                       Hub
memory:
                       Main Memory
unknown:
                       FPU
                       DMA controller
                       PIC
                       Timer
                       Keyboard controller
                       PS/2 Controller
                       Intel Communication controller
                       Intel SMBus
  /dev/input/event6    Bison Lenovo EasyCamera