Messages in this thread | | | Date | Fri, 01 Aug 2014 19:46:17 +0200 | From | Maarten Lankhorst <> | Subject | Re: [PATCH 09/19] drm/radeon: handle lockup in delayed work, v2 |
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On 01-08-14 18:35, Christian König wrote: > Am 31.07.2014 um 17:33 schrieb Maarten Lankhorst: >> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com> >> --- >> V1 had a nasty bug breaking gpu lockup recovery. The fix is not >> allowing radeon_fence_driver_check_lockup to take exclusive_lock, >> and kill it during lockup recovery instead. > > That looks like the delayed work starts running as soon as we submit a fence, and not when it's needed for waiting. > > Since it's a backup for failing IRQs I would rather put it into radeon_irq_kms.c and start/stop it when the IRQs are started/stoped.
The delayed work is not just for failing irq's, it's also the handler that's used to detect lockups, which is why I trigger after processing fences, and reset the timer after processing.
Specifically what happened was this scenario:
- lock up occurs - write lock taken by gpu_reset - delayed work runs, tries to acquire read lock, blocks - gpu_reset tries to cancel delayed work synchronously - has to wait for delayed work to finish -> deadlock
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