[bugzilla-daemon at bugzilla.kernel.org: [Bug 209149] New: "iommu/vt-d: Enable PCI ACS for platform opt in hint" makes NVMe config space not accessible after S3]

[Raj, Ashok]

Hi Bjorn


On Wed, Sep 23, 2020 at 11:03:27AM -0500, Bjorn Helgaas wrote:
> [+cc IOMMU and NVMe folks]
> 
> Sorry, I forgot to forward this to linux-pci when it was first
> reported.
> 
> Apparently this happens with v5.9-rc3, and may be related to
> 50310600ebda ("iommu/vt-d: Enable PCI ACS for platform opt in hint"),
> which appeared in v5.8-rc3.
> 
> There are several dmesg logs and proposed patches in the bugzilla, but
> no analysis yet of what the problem is.  From the first dmesg
> attachment (https://bugzilla.kernel.org/attachment.cgi?id=292327):

We have been investigating this internally as well. It appears maybe the
specupdate for Cometlake is missing the errata documention. The offsets
were wrong in some of them, and if its the same issue its likely cause. 

Will nudge the hw folks to hunt that down :-(.

Cheers,
Ashok