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From: Jason Gunthorpe <jgg@nvidia.com>
To: Pranjal Shrivastava <praan@google.com>
Cc: iommu@lists.linux.dev, Will Deacon <will@kernel.org>,
	Joerg Roedel <joro@8bytes.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Mostafa Saleh <smostafa@google.com>,
	Nicolin Chen <nicolinc@nvidia.com>,
	Daniel Mentz <danielmentz@google.com>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v9 09/12] iommu/arm-smmu-v3: Implement pm_runtime & system sleep ops
Date: Tue, 25 Aug 2026 17:17:01 -0300	[thread overview]
Message-ID: <20260825201701.GG3325090@nvidia.com> (raw)
In-Reply-To: <ao3kxwbwB9GC3EOM@google.com>

On Tue, Aug 25, 2026 at 06:53:59PM +0000, Pranjal Shrivastava wrote:

> > I agree.. I think there are only two options?
> >  1) After GBPA=Abort ATS requests are blocked, so you could full
> >     invalidate all the device ATC's and now it is safe to ignore
> >     ATC_INV
> >  2) Just don't perform suspend once ATS is activated
> 
> This is a little tricky, I'm leaning towards 1) since edge devices can
> have ATS enabled

Oh really? Surprising..

> However, the EP might've entered it's low power state by the time we 
> reach smmu's suspend. I'm not sure if we should be waking up the EP for
> ATC INV All (or if it would even wake up in such a case?)

Is its power down explicit? Could the PM stuff trigger wiping the ATC
and blocking DMA for a single device before allowing it to power down?

Jason


  reply	other threads:[~2026-08-25 20:17 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-28 21:09 [PATCH v9 00/12] iommu/arm-smmu-v3: Implement Runtime/System Sleep ops Pranjal Shrivastava
2026-07-28 21:09 ` [PATCH v9 01/12] iommu/arm-smmu-v3: Refactor arm_smmu_setup_irqs Pranjal Shrivastava
2026-08-25 16:36   ` Jason Gunthorpe
2026-08-25 17:35     ` Pranjal Shrivastava
2026-08-25 18:47       ` Nicolin Chen
2026-08-25 19:01         ` Pranjal Shrivastava
2026-07-28 21:09 ` [PATCH v9 02/12] iommu/arm-smmu-v3: Add a helper to drain cmd queues Pranjal Shrivastava
2026-08-25 16:36   ` Jason Gunthorpe
2026-08-25 17:37     ` Pranjal Shrivastava
2026-08-25 18:20       ` Nicolin Chen
2026-08-25 18:57         ` Pranjal Shrivastava
2026-07-28 21:09 ` [PATCH v9 03/12] iommu/tegra241-cmdqv: Add a helper to drain VCMDQs Pranjal Shrivastava
2026-07-28 21:09 ` [PATCH v9 04/12] iommu/tegra241-cmdqv: Restore PROD and CONS after resume Pranjal Shrivastava
2026-07-28 21:09 ` [PATCH v9 05/12] iommu/arm-smmu-v3: Cache and restore MSI config Pranjal Shrivastava
2026-08-25 16:36   ` Jason Gunthorpe
2026-08-25 18:01     ` Pranjal Shrivastava
2026-07-28 21:09 ` [PATCH v9 06/12] iommu/arm-smmu-v3: Handle gerror during suspend Pranjal Shrivastava
2026-08-25 16:36   ` Jason Gunthorpe
2026-08-25 18:06     ` Pranjal Shrivastava
2026-07-28 21:09 ` [PATCH v9 07/12] iommu/arm-smmu-v3: Add CMDQ_PROD_STOP_FLAG to gate CMDQ submissions Pranjal Shrivastava
2026-08-25 16:36   ` Jason Gunthorpe
2026-08-25 18:38     ` Pranjal Shrivastava
2026-07-28 21:09 ` [PATCH v9 08/12] iommu/tegra241-cmdqv: Add a helper to quiesce VCMDQs Pranjal Shrivastava
2026-08-25 16:36   ` Jason Gunthorpe
2026-08-25 18:46     ` Pranjal Shrivastava
2026-07-28 21:09 ` [PATCH v9 09/12] iommu/arm-smmu-v3: Implement pm_runtime & system sleep ops Pranjal Shrivastava
2026-08-25 16:36   ` Jason Gunthorpe
2026-08-25 18:53     ` Pranjal Shrivastava
2026-08-25 20:17       ` Jason Gunthorpe [this message]
2026-08-26 11:51         ` Pranjal Shrivastava
2026-08-26 13:47           ` Jason Gunthorpe
2026-08-26 14:17             ` Pranjal Shrivastava
2026-07-28 21:09 ` [PATCH v9 10/12] iommu/arm-smmu-v3: Enable pm_runtime and setup devlinks Pranjal Shrivastava
2026-07-28 21:09 ` [PATCH v9 11/12] iommu/arm-smmu-v3: Invoke pm_runtime before hw access Pranjal Shrivastava
2026-07-28 21:09 ` [PATCH v9 12/12] iommu/arm-smmu-v3: Add KUnit unit tests for Runtime PM Pranjal Shrivastava
2026-08-25 13:33 ` [PATCH v9 00/12] iommu/arm-smmu-v3: Implement Runtime/System Sleep ops Jason Gunthorpe
2026-08-25 18:50   ` Pranjal Shrivastava
2026-08-25 20:14     ` Jason Gunthorpe
2026-08-26 11:55       ` Pranjal Shrivastava

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