Created attachment 97279 [details]
Gpu crash dump and Xorg log

I am running a debian/sid linux on a laptop with an optimus nvidia card 
(nvidia GeForce GT 640 2GB) using the NOUVEAU driver.

From time to time kwin crashes. 

Also, while running, the cursor sometimes turns to a 2cm X 2cm white block.

Following is the message from dmesg. 

The GPU crash dump and the Xorg.0.log is attached.

---------------------------------------------------------------------------
[ 2322.266868] [drm] stuck on render ring
[ 2322.266887] [drm] GPU crash dump saved to /sys/class/drm/card0/error
[ 2322.266888] [drm] GPU hangs can indicate a bug anywhere in the entire gfx stack, including userspace.
[ 2322.266889] [drm] Please file a _new_ bug report on bugs.freedesktop.org against DRI -> DRM/Intel
[ 2322.266890] [drm] drm/i915 developers can then reassign to the right component if it's not a kernel issue.
[ 2322.266891] [drm] The gpu crash dump is required to analyze gpu hangs, so please always attach it.
[ 2322.271361] [drm:i915_set_reset_status] *ERROR* render ring hung inside bo (0x3389000 ctx 1) at 0x3389004
[ 2328.258782] [drm] stuck on render ring
[ 2328.258894] [drm:i915_set_reset_status] *ERROR* render ring hung inside bo (0xa70c000 ctx 1) at 0xa70c2ac
[ 2328.258898] [drm:i915_context_is_banned] *ERROR* context hanging too fast, declaring banned!
----------------------------------------------------------------------------

Regards,

George Famelis