Re: [PATCH 0/2] PCI: Fix ACS enablement for Root Ports in DT platforms

[Jason Gunthorpe]

On Wed, Sep 10, 2025 at 11:09:19PM +0530, Manivannan Sadhasivam via B4 Relay wrote:
> This issue was already found and addressed with a quirk for a different device
> from Microsemi with 'commit, aa667c6408d2 ("PCI: Workaround IDT switch ACS
> Source Validation erratum")'. Apparently, this issue seems to be documented in
> the erratum #36 of IDT 89H32H8G3-YC, which is not publicly available.

This is a pretty broken device! I'm not sure this fix is good enough
though.

For instance if you reset a downstream device it should loose its RID
and then the config cycles waiting for reset to complete will trigger SV
and reset will fail?

Maybe a better answer is to say these switches don't support SV and
prevent the kernel from enabling it in the first place?

Jason