Created attachment 123214 [details]
/sys/class/drm/card0/error

While watching Youtube in Chromium on an Intel NUC6i5SYH (Skylake) running Arch Linux with an Intel DRM Nightly kernel (compiled on Thu Apr 21 15:35:07 CEST 2016), this happens:

[32433.777491] [drm] stuck on render ring
[32433.780134] [drm] GPU HANG: ecode 9:0:0x85dffffb, in Xorg [655], reason: Engine(s) hung, action: reset
[32433.780140] [drm] GPU hangs can indicate a bug anywhere in the entire gfx stack, including userspace.
[32433.780144] [drm] Please file a _new_ bug report on bugs.freedesktop.org against DRI -> DRM/Intel
[32433.780148] [drm] drm/i915 developers can then reassign to the right component if it's not a kernel issue.
[32433.780151] [drm] The gpu crash dump is required to analyze gpu hangs, so please always attach it.
[32433.780155] [drm] GPU crash dump saved to /sys/class/drm/card0/error
[32433.782525] drm/i915: Resetting chip after gpu hang
[32435.764178] [drm] RC6 on
[32443.777620] [drm] stuck on render ring
[32443.780067] [drm] GPU HANG: ecode 9:0:0x85dffffb, in Xorg [655], reason: Engine(s) hung, action: reset
[32443.781572] drm/i915: Resetting chip after gpu hang
[32445.744378] [drm] RC6 on
[32453.777805] [drm] stuck on render ring
[32453.780239] [drm] GPU HANG: ecode 9:0:0x85dffffb, in Xorg [655], reason: Engine(s) hung, action: reset
[32453.782198] drm/i915: Resetting chip after gpu hang
[32455.764444] [drm] RC6 on
[32463.764670] [drm] stuck on render ring
[32463.766750] [drm] GPU HANG: ecode 9:0:0x85dffffb, in Xorg [655], reason: Engine(s) hung, action: reset
[32463.769039] drm/i915: Resetting chip after gpu hang
[32465.764619] [drm] RC6 on
[32473.778030] [drm] stuck on render ring
[32473.779751] [drm] GPU HANG: ecode 9:0:0x85dffffb, in Xorg [655], reason: Engine(s) hung, action: reset
[32473.779970] [drm:i915_set_reset_status] *ERROR* gpu hanging too fast, banning!
[32473.781369] drm/i915: Resetting chip after gpu hang
[32475.778323] [drm] RC6 on

During this time the system froze (e.g. no mouse), although the audio from Youtube continued. Afterwards it unfroze, but i had to restart Chromium because the browser window would not render anymore. 

Besides the above, the drm-nightly kernels of the past 2 weeks or so, have been running without errors.