Got this after resuming from hibernate on v3.15-rc2:
[drm] stuck on render ring
[drm] GPU HANG: ecode 0:0xf7e5ecbe, in Xorg , reason: Ring hung, action: reset
[drm] GPU hangs can indicate a bug anywhere in the entire gfx stack, including userspace.
[drm] Please file a _new_ bug report on bugs.freedesktop.org against DRI -> DRM/Intel
[drm] drm/i915 developers can then reassign to the right component if it's not a kernel issue.
[drm] The gpu crash dump is required to analyze gpu hangs, so please always attach it.
[drm] GPU crash dump saved to /sys/class/drm/card0/error
Created attachment 98052 [details]
Attaching gpu crash dump
Bjorn, any chance for a bisect, or is this only sporadic?
Sorry, this has only happened once. So I am not even sure it is a regression. Don't think I added that label on this bug report?
I added it since presumably you'd have reported it earlier if it wasn't a regression ;-) Also we've frobbed around the gpu memory layout a bit in 3.15 which would make your bug more likely.
I think we'll keep this open for a bit longer, but if you can't reproduce we need to close it due to insufficient data unfortunately.
On second thoughts, this is bug 76554 as the ring failed to start properly. Notice that the registers read back garbage, and those garbage reads occurred during ring-init upon resume: ring->head: 0xffe00000
*** This bug has been marked as a duplicate of bug 76554 ***