I'm also having this bug, running Ubuntu 10.04, with latest kernel available (2.6.38-10 pae).

===
=== Error message
===
[43327.520095] [drm:i915_hangcheck_elapsed] *ERROR* Hangcheck timer elapsed... GPU hung
 [43327.524194] [drm:i915_do_wait_request] *ERROR* i915_do_wait_request returns -11 (awaiting 1615781 at 1615776, next 1615783)
[43329.324014] [drm:i915_hangcheck_elapsed] *ERROR* Hangcheck timer elapsed... GPU hung
[43329.948017] [drm:i915_reset] *ERROR* Failed to reset chip.


=== 
=== System OS
===
Linux Raistlin4 2.6.38-10-generic-pae #46~lucid1-Ubuntu SMP Wed Jul 6 20:34:59 UTC 2011 i686 GNU/Linux

===
=== Video Hardware
===
     *-pci
          description: Host bridge
          product: Mobile 4 Series Chipset Memory Controller Hub
          vendor: Intel Corporation
          physical id: 100
          bus info: pci@0000:00:00.0
          version: 07
          width: 32 bits
          clock: 33MHz
          configuration: driver=agpgart-intel
          resources: irq:0
        *-display:0
             description: VGA compatible controller
             product: Mobile 4 Series Chipset Integrated Graphics Controller
             vendor: Intel Corporation
             physical id: 2
             bus info: pci@0000:00:02.0
             version: 07
             width: 64 bits
             clock: 33MHz
             capabilities: bus_master cap_list rom
             configuration: driver=i915 latency=0
             resources: irq:45 memory:d0000000-d03fffff memory:c0000000-cfffffff ioport:40f0(size=8)
        *-display:1 UNCLAIMED
             description: Display controller
             product: Mobile 4 Series Chipset Integrated Graphics Controller
             vendor: Intel Corporation
             physical id: 2.1
             bus info: pci@0000:00:02.1
             version: 07
             width: 64 bits
             clock: 33MHz
             capabilities: bus_master cap_list
             configuration: latency=0
             resources: memory:d0400000-d04fffff

===
=== Xorg main packages
===
xserver-xorg                                                   1:7.5+5ubuntu1
xserver-xorg-video-intel                              2:2.9.1-3ubuntu5
libdrm-dev                                                       2.4.18-1ubuntu3 
libdrm-intel1                                                   2.4.18-1ubuntu3   
libdrm-nouveau1                                            2.4.18-1ubuntu3 
libdrm-radeon1                                               2.4.18-1ubuntu3   
libdrm2                                                             2.4.18-1ubuntu3             

===
=== Xorg -version
===
X.Org X Server 1.7.6
Release Date: 2010-03-17
X Protocol Version 11, Revision 0
Build Operating System: Linux 2.6.24-27-server i686 Ubuntu
Current Operating System: Linux Raistlin4 2.6.38-10-generic-pae #46~lucid1-Ubuntu SMP Wed Jul 6 20:34:59 UTC 2011 i686
Kernel command line: BOOT_IMAGE=/boot/vmlinuz-2.6.38-10-generic-pae root=UUID=df98d7ae-47a5-4b85-87b5-5fdcef49a7f8 ro quiet splash
Build Date: 08 March 2011  08:22:50AM
xorg-server 2:1.7.6-2ubuntu7.6 (For technical support please see http://www.ubuntu.com/support) 
Current version of pixman: 0.16.4


   Any suggestion ?
   Thanks,
-- 
Thierry