Subject: Re: [PATCH v2 6/7] iommu/arm-smmu-v3: Introduce master->ats_broken flag

From: Nicolin Chen <[email-masked]>
Date: Wed, 18 Mar 2026 13:00:24 -0700

On Wed, Mar 18, 2026 at 07:39:53AM +0000, Tian, Kevin wrote:
> > From: Nicolin Chen <[email-masked]>
> > Sent: Wednesday, March 18, 2026 3:16 AM
> > 
> > @@ -3060,6 +3079,14 @@ static bool arm_smmu_ats_supported(struct
> > arm_smmu_master *master)
> >  	if (!(fwspec->flags & IOMMU_FWSPEC_PCI_RC_ATS))
> >  		return false;
> > 
> > +	/*
> > +	 * Reject any new ATS request because ATC invalidation was timed
> > out.
> > +	 * The PCI device should go through a recovery (reset) and notify the
> > +	 * SMMUv3 driver via a reset_device_done callback.
> > +	 */
> > +	if (READ_ONCE(master->ats_broken))
> > +		return false;
> > +
> 
> "Reject any new ATS request" means any new request to enable ATS
> on this device, instead of rejecting any new ATS translation request,
> correct? next patch does the actual work to block ATS...

Yes. We won't call pci_enable_ats() due to !arm_smmu_ats_supported.
So, there shouldn't be any new ATS request any more.

I will change it to:
	/*
	 * Do not enable ATS if master->ats_broken is set. The PCI device should
	 * go through a recovery (reset) that shall notify the SMMUv3 driver via
	 * a reset_device_done callback.
	 */

Thanks
Nicolin