Re: [PATCH] arm64: dts: qcom: x1e80100: enable GICv3 ITS for PCIe

[Johan Hovold <johan@kernel.org>]

[ +CC: Mani ]

On Thu, Jul 11, 2024 at 11:58:08AM +0200, Johan Hovold wrote:
> On Thu, Jul 11, 2024 at 11:54:15AM +0200, Konrad Dybcio wrote:
> > On 11.07.2024 11:02 AM, Johan Hovold wrote:
> > > The DWC PCIe controller can be used with its internal MSI controller or
> > > with an external one such as the GICv3 Interrupt Translation Service
> > > (ITS).
> > > 
> > > Add the msi-map properties needed to use the GIC ITS. This will also
> > > make Linux switch to the ITS implementation, which allows for assigning
> > > affinity to individual MSIs.

> > X1E CRD throws tons of correctable errors with this on PCIe6a:

> What branch are you using? Abel reported seeing this with his branch
> which has a few work-in-progress patches that try to enable 4-lane PCIe.
> 
> There are no errors with my wip branch based on rc7, and I have the same
> drive as Abel.

For some reason I don't get these errors on my machine, but this has now
been confirmed by two other people running my rc branch (including Abel)
so something is broken here, for example, with the PHY settings.

I saw five correctable errors once, when running linux-next, but it took
several minutes and they were still minutes apart.

> Also note that the errors happen also without this patch applied, they
> are just being reported now.

I guess we need to track down what is causing these errors before
enabling ITS (and thereby the error reporting). 

At least L0s is not involved here, as it was with sc8280xp, as the
NVMe controllers in question do not support it.

Perhaps something is off because we're running the link at half width?

Johan