Re: IOMMU faults after S3

[Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>]

On Fri, Mar 27, 2026 at 10:56:43AM +0000, Teddy Astie wrote:
> Le 27/03/2026 à 11:19, Marek Marczykowski-Górecki a écrit :
> > Hi,
> >
> > I noticed that on some systems, there are a lot of IOMMU faults after
> > S3. I can see it also on a laptop with MTL, but it affects also the ADL
> > gitlab runner:
> >
> >      https://gitlab.com/xen-project/hardware/xen/-/jobs/13661033722
> >      (XEN) [   37.201160] [VT-D]DMAR:[DMA Write] Request device 
> > [0000:00:1e.6] fault addr 0
> >      (XEN) [   37.201164] [VT-D]DMAR: reason 02 - Present bit in context 
> > entry is clear
> >      (XEN) [   37.202332] [VT-D]DMAR:[DMA Write] Request device 
> > [0000:00:1e.6] fault addr 0
> >      (XEN) [   37.202339] [VT-D]DMAR: reason 02 - Present bit in context 
> > entry is clear
> >
> > Interestingly, the 0000:00:1e.6 device is not even listed by lspci.
> >
> > The issue is present only on staging, not staging-4.21.
> >
> 
> Is there a 1e.0 device ? That could be a "phantom" PCI device.

On ADL - no, there is 1c.2, and then 1f.0.
But on that MTL, yes:
00:1e.0 Communication controller [0780]: Intel Corporation Meteor Lake-P Serial 
IO UART Controller #0 [8086:7e25] (rev 20)

(I wish there would be a connector populated on the board...)

-- 
Best Regards,
Marek Marczykowski-Górecki
Invisible Things Lab

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