Messages in this thread | | | Subject | Re: [PATCH v2] iommu/arm-smmu: fix "hang" when games exit | From | Robin Murphy <> | Date | Mon, 28 Oct 2019 22:51:53 +0000 |
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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: >> >> Hi Rob, >> >> 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".
Robin.
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