Ubuntu 10.04 Lucid Lynx used to run fine on my computer. Since a few weeks, my X server crashes out of the blue while the computer is idle and I'm logged into a Gnome session. (I'm then greeted with a new GDM login prompt). After the crash, /var/log/gdm/:0.log.1 has the following:

Fatal server error: Failed to submit batchbuffer: Input/output error

Please consult the The X.Org Foundation support at http://wiki.x.org for help.

~/.xsession-errors.old has symptoms of X clinets dying:

nm-applet: Fatal IO error 11 (Die Ressource ist zur Zeit nicht verfügbar) on X server :0.0.

dmesg says:

[191848.390081] [drm:i915_hangcheck_elapsed] ERROR Hangcheck timer elapsed... GPU hung

[191848.390086] render error detected, EIR: 0x00000010

[191848.390088] IPEIR: 0x00000000

[191848.390090] IPEHR: 0x01800002

[191848.390091] INSTDONE: 0xffffffff

[191848.390093] INSTPS: 0x8001e020

[191848.390095] INSTDONE1: 0xbfffffff

[191848.390097] ACTHD: 0x0a47b014

[191848.390099] page table error

[191848.390100] PGTBL_ER: 0x00000002

[191848.390103] [drm:i915_handle_error] ERROR EIR stuck: 0x00000010, masking

[191848.390127] [drm:i915_do_wait_request] ERROR i915_do_wait_request returns -5 > (awaiting 5617217 at 5617205)

Is this a known problem that can be traced back to the X server from Ubuntu repositories? How would I debug this?

Edit: There's a relevant bug on LP.