Re: [PATCH 2/2] PCI: dw-rockchip: hide broken ATS capability

["Krzysztof Wilczyński" <kw@linux.com>]

Hello,

> > When running the rk3588 in endpoint mode, with an Intel host with IOMMU
> > enabled, the host side prints:
> > DMAR: VT-d detected Invalidation Time-out Error: SID 0
> > 
> > When running the rk3588 in endpoint mode, with an AMD host with IOMMU
> > enabled, the host side prints:
> > iommu ivhd0: AMD-Vi: Event logged [IOTLB_INV_TIMEOUT device=63:00.0 address=0x42b5b01a0]
> 
> Maybe add a blank line and indent the message since it's quoted
> material?  E.g.,
> 
>   When running the rk3588 in endpoint mode, with an Intel IOMMU, the
>   host side prints:
> 
>     DMAR: VT-d detected Invalidation Time-out Error: SID 0
> 
>   When running the rk3588 in endpoint mode, with an AMD ...
> 
>     iommu ivhd0: AMD-Vi: Event logged [IOTLB_INV_TIMEOUT device=63:00.0 address=0x42b5b01a0]
> 
> Too bad DMAR isn't smart enough to include a device ID in its message ;)
> 
> Can you include something here about what the issue is?  Based on the
> subject line and the patch, I assume something is wrong with the ATS
> Capability?  I guess this is some kind of rk3588 defect, right?
> 
> > Usually, to handle these issues, we add a quirk for the PCI vendor and
> > device ID in drivers/pci/quirks.c with quirk_no_ats(). That is because
> > we cannot usually modify the capabilities on the EP side.
> > 
> > In this case, we can modify the capabilties on the EP side. Thus, hide the
> > broken ATS capability on rk3588 when running in EP mode. That way,
> > we don't need any quirk on the host side, and we see no errors on the host
> > side, and we can run pci_endpoint_test successfully, with the IOMMU
> > enabled on the host side.
> 
> s/capabilties/capabilities/

If there are no code changes here, then I can update the commit log
directly on the branch itself once applied.

Thank you!

	Krzysztof