Re: [PATCH v2] arm64: dts: qcom: sa8540p-ride: disable pcie2a node

[Andrew Halaney]

On Thu, Jan 11, 2024 at 09:02:41AM -0500, Brian Masney wrote:
> On Tue, Jan 09, 2024 at 10:20:50AM -0500, Lucas Karpinski wrote:
> > pcie2a and pcie3a both cause interrupt storms to occur. However, when
> > both are enabled simultaneously, the two combined interrupt storms will
> > lead to rcu stalls. Red Hat is the only company still using this board
> > and since we still need pcie3a, just disable pcie2a.
> > 
> > Signed-off-by: Lucas Karpinski <lkarpins@xxxxxxxxxx>
> 
> Reviewed-by: Brian Masney <bmasney@xxxxxxxxxx>
> 
> To elaborate further: Leaving both pcie2a and pcie3a enabled will lead
> to rcu stalls and the board fails to boot when both are enabled. We
> have the latest firmware that we've been able to get from QC.
> Disabling one of the pcie nodes works around the boot issue. There's
> nothing interesting on pcie2a on the development board, and pcie3a is
> enabled because it has 10GB ethernet that works upstream.
> 
> The interrupt storm on pcie3a can still occur on this platform, however
> that's a separate issue.

Related work-around to that in case anyone is interested in the paper
trail:

    https://lore.kernel.org/all/89c13962f5502a89d48f1efb7a6203d155a7e18d.camel@xxxxxxxxxx/