From: Rob Clark <robdclark@chromium.org>
To: Will Deacon <will@kernel.org>
Cc: freedreno <freedreno@lists.freedesktop.org>,
Joerg Roedel <joro@8bytes.org>,
iommu@lists.linux-foundation.org,
open list <linux-kernel@vger.kernel.org>,
Rob Clark <robdclark@gmail.com>,
Robin Murphy <robin.murphy@arm.com>,
"moderated list:ARM SMMU DRIVERS"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v2] iommu/arm-smmu: fix "hang" when games exit
Date: Mon, 28 Oct 2019 15:38:04 -0700 [thread overview]
Message-ID: <CAJs_Fx7zRWsTPiAg0PFt+8nJPpHpzSkxW6XMMJwozVO6vyB78A@mail.gmail.com> (raw)
In-Reply-To: <20191028222042.GB8532@willie-the-truck>
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"?
BR,
-R
>
> > Signed-off-by: Rob Clark <robdclark@chromium.org>
> > ---
> > v1: original
> > v2: unconditionally use autosuspend, rather than deciding based on what
> > consumer does
> >
> > drivers/iommu/arm-smmu.c | 5 ++++-
> > 1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> > index 3f1d55fb43c4..b7b41f5001bc 100644
> > --- a/drivers/iommu/arm-smmu.c
> > +++ b/drivers/iommu/arm-smmu.c
> > @@ -289,7 +289,7 @@ static inline int arm_smmu_rpm_get(struct arm_smmu_device *smmu)
> > static inline void arm_smmu_rpm_put(struct arm_smmu_device *smmu)
> > {
> > if (pm_runtime_enabled(smmu->dev))
> > - pm_runtime_put(smmu->dev);
> > + pm_runtime_put_autosuspend(smmu->dev);
> > }
> >
> > static struct arm_smmu_domain *to_smmu_domain(struct iommu_domain *dom)
> > @@ -1445,6 +1445,9 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
> > /* Looks ok, so add the device to the domain */
> > ret = arm_smmu_domain_add_master(smmu_domain, fwspec);
>
> Please can you put a comment here explaining what this is doing? An abridged
> version of the commit message is fine.
>
> > + pm_runtime_set_autosuspend_delay(smmu->dev, 20);
> > + pm_runtime_use_autosuspend(smmu->dev);
>
> Cheers,
>
> Will
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next prev parent reply other threads:[~2019-10-28 22:38 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-07 17:50 [PATCH] iommu/arm-smmu: fix "hang" when games exit Rob Clark
2019-09-10 15:01 ` Robin Murphy
2019-09-10 15:45 ` Rob Clark
2019-10-07 20:49 ` [PATCH v2] " Rob Clark
2019-10-09 10:10 ` Robin Murphy
2019-10-28 22:20 ` Will Deacon
2019-10-28 22:38 ` Rob Clark [this message]
2019-10-28 22:51 ` Robin Murphy
2019-10-29 11:15 ` Will Deacon
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