Messages in this thread | | | Date | Tue, 29 Oct 2019 11:15:56 +0000 | From | Will Deacon <> | Subject | Re: [PATCH v2] iommu/arm-smmu: fix "hang" when games exit |
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On Mon, Oct 28, 2019 at 10:51:53PM +0000, Robin Murphy wrote: > On 2019-10-28 10:38 pm, Rob Clark wrote: > > On Mon, Oct 28, 2019 at 3:20 PM Will Deacon <will@kernel.org> wrote: > > > On Mon, Oct 07, 2019 at 01:49:06PM -0700, Rob Clark wrote: > > > > From: Rob Clark <robdclark@chromium.org> > > > > > > > > When games, browser, or anything using a lot of GPU buffers exits, there > > > > can be many hundreds or thousands of buffers to unmap and free. If the > > > > GPU is otherwise suspended, this can cause arm-smmu to resume/suspend > > > > for each buffer, resulting 5-10 seconds worth of reprogramming the > > > > context bank (arm_smmu_write_context_bank()/arm_smmu_write_s2cr()/etc). > > > > To the user it would appear that the system just locked up. > > > > > > > > A simple solution is to use pm_runtime_put_autosuspend() instead, so we > > > > don't immediately suspend the SMMU device. > > > > > > Please can you reword the subject to be a bit more useful? The commit > > > message is great, but the subject is a bit like "fix bug in code" to me. > > > > yeah, not the best $subject, but I wasn't quite sure how to fit > > something better in a reasonable # of chars.. maybe something like: > > "iommu/arm-smmu: optimize unmap but avoiding toggling runpm state"? > > FWIW, I'd be inclined to frame it as something like "avoid pathological RPM > behaviour for unmaps".
LGTM!
Will
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