Bug 77892

Summary:	[RV635] when GPU locks up, reset happens but X is unresponsive except mouse
Product:	DRI	Reporter:	Shawn Starr <shawn.starr>
Component:	DRM/Radeon	Assignee:	Default DRI bug account <dri-devel>
Status:	RESOLVED INVALID	QA Contact:
Severity:	critical
Priority:	medium
Version:	unspecified
Hardware:	x86-64 (AMD64)
OS:	Linux (All)
Whiteboard:
i915 platform:		i915 features:

Description Shawn Starr 2014-04-24 13:22:43 UTC

For a long time now, I don't recall which 3.x broke this but there's been many changes since and now, when the GPU does randomly reset, the display goes blank, X display is restored, but I can only move mouse, cannot interact with X.

Can someone point me to some debugging approaches to see if there's some lock being held somewhere thats causing this?

I am able to ssh into the laptop so, this seems to point to some sort of lock thats not released.

Bisecting radeon drm will be difficult if I have to start from near the beginning of r600g drm support.

Comment 1 Marek Olšák 2014-04-24 13:47:41 UTC

This looks like a deadlock in the kernel. I guess some fence is not signalled during the reset, so GEM_WAIT_IDLE never returns.

Comment 2 Shawn Starr 2014-04-24 18:41:20 UTC

How to debug? Do we have a flag to show lock/unlock states so i can try to pair who forgot to release lock? is it X? is it drm driver?

Comment 3 Shawn Starr 2014-04-24 18:44:04 UTC

Even as of 3.14 final, this happens, 3.15-rc2 right now is too unstable for me to boot into.

Comment 4 Shawn Starr 2016-08-31 04:06:30 UTC

I don't use that dGPU much anymore, closing, and probably a lot of fixes have occurred which may have solved this also.

I haven't tried a recent 4.8 kernel to confirm, but I still could for fun. closing.

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