Created attachment 111180 [details]
xzipped dump of /sys/class/drm/card0/error

I was scrolling a video file in mpv player (version 0.7.2) and at some point the system appeared to become frozen. After abount 1 or 2 seconds it unfroze and continued to work normally. I was not able to reproduce the bug. 

Here is an excerpt from the system journal:

Dec 22 19:02:37 note kernel: [drm] stuck on render ring
Dec 22 19:02:38 note kernel: [drm] GPU HANG: ecode 0:0x00d18eba, in Xorg.bin [251], reason: Ring hung, action: reset
Dec 22 19:02:38 note kernel: [drm] GPU hangs can indicate a bug anywhere in the entire gfx stack, including userspace.
Dec 22 19:02:38 note kernel: [drm] Please file a _new_ bug report on bugs.freedesktop.org against DRI -> DRM/Intel
Dec 22 19:02:38 note kernel: [drm] drm/i915 developers can then reassign to the right component if it's not a kernel issue.
Dec 22 19:02:38 note kernel: [drm] The gpu crash dump is required to analyze gpu hangs, so please always attach it.
Dec 22 19:02:38 note kernel: [drm] GPU crash dump saved to /sys/class/drm/card0/error

My system is:
Linux note 3.17.6-1-ARCH #1 SMP PREEMPT Sun Dec 7 23:43:32 UTC 2014 x86_64 GNU/Linux