[PATCH v9 09/12] iommu/arm-smmu-v3: Implement pm_runtime & system sleep ops

[Jason Gunthorpe]

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