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<b><a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - [CI][DRMTIP] igt@gem_exec_schedule@semaphore-user - warn - Failed assertion: !"GPU hung""
href="https://bugs.freedesktop.org/show_bug.cgi?id=110367#c5">Comment # 5</a>
on <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - [CI][DRMTIP] igt@gem_exec_schedule@semaphore-user - warn - Failed assertion: !"GPU hung""
href="https://bugs.freedesktop.org/show_bug.cgi?id=110367">bug 110367</a>
from <span class="vcard"><a class="email" href="mailto:martin.peres@free.fr" title="Martin Peres <martin.peres@free.fr>"> <span class="fn">Martin Peres</span></a>
</span></b>
<pre>(In reply to Chris Wilson from <a href="show_bug.cgi?id=110367#c2">comment #2</a>)
<span class="quote">> commit bac24f59f45419a3853af2f58130cb82b7bdca64
> Author: Chris Wilson <<a href="mailto:chris@chris-wilson.co.uk">chris@chris-wilson.co.uk</a>>
> Date: Fri Mar 29 13:40:24 2019 +0000
>
> drm/i915/execlists: Enable coarse preemption boundaries for gen8
>
> When we introduced preemption, we chose to keep it disabled for gen8 as
> supporting preemption inside GPGPU user batches required various w/a in
> userspace. Since then, the desire to preempt long queues of requests
> between batches (e.g. within busywaiting semaphores) has grown. So allow
> arbitration within the busywaits and between requests, but disable
> arbitration within user batches so that we can preempt between requests
> and not risk breaking GPGPU.
>
> However, since this preemption is much coarser and doesn't interfere
> with userspace, we decline to include it amongst the scheduler
> capabilities. (This is also required for us to skip over the preemption
> selftests that expect to be able to preempt user batches.)
>
> Michal suggested that we could perhaps allow preemption inside gen8
> userspace batches if we can satisfy ourselves that the default
> preemption settings are viable with existing userspace (principally
> OpenCL which already should carry any known workaround). We could then
> merge the two code paths back into one, even dropping the artifical
> has-preemption device feature flag.
>
> Testcase: igt/gem_exec_scheduler/semaphore-user
> References: beecec901790 ("drm/i915/execlists: Preemption!")
> Fixes: e88619646971 ("drm/i915: Use HW semaphores for inter-engine
> synchronisation on gen8+")
> Signed-off-by: Chris Wilson <<a href="mailto:chris@chris-wilson.co.uk">chris@chris-wilson.co.uk</a>>
> Cc: Michal Winiarski <<a href="mailto:michal.winiarski@intel.com">michal.winiarski@intel.com</a>>
> Cc: Tvrtko Ursulin <<a href="mailto:tvrtko.ursulin@intel.com">tvrtko.ursulin@intel.com</a>>
> Reviewed-by: Michal Winiarski <<a href="mailto:michal.winiarski@intel.com">michal.winiarski@intel.com</a>> #irc
> Reviewed-by: Tvrtko Ursulin <<a href="mailto:tvrtko.ursulin@intel.com">tvrtko.ursulin@intel.com</a>>
> Link:
> <a href="https://patchwork.freedesktop.org/patch/msgid/20190329134024.5254-1">https://patchwork.freedesktop.org/patch/msgid/20190329134024.5254-1</a>-
> <a href="mailto:chris@chris-wilson.co.uk">chris@chris-wilson.co.uk</a></span >
Thanks, the bug was seen twice on one drmtip run, and not for the following 6
runs. This means we are over the 10x rule and can consider this fixed. Thanks!</pre>
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