Bug 77892 - [RV635] when GPU locks up, reset happens but X is unresponsive except mouse
Summary: [RV635] when GPU locks up, reset happens but X is unresponsive except mouse
Status: RESOLVED INVALID
Alias: None
Product: DRI
Classification: Unclassified
Component: DRM/Radeon (show other bugs)
Version: unspecified
Hardware: x86-64 (AMD64) Linux (All)
: medium critical
Assignee: Default DRI bug account
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Reported: 2014-04-24 13:22 UTC by Shawn Starr
Modified: 2016-08-31 04:06 UTC (History)
0 users

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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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