Re: [PATCH 1/2] amd_nb: Add PCI ID for family 19h model 78h

[Bjorn Helgaas]

On Thu, Apr 27, 2023 at 12:33:36AM -0500, Mario Limonciello wrote:
> s2idle previously worked on this system, but it regressed in kernel
> 6.4 due to commit 310e782a99c7 ("platform/x86/amd: pmc: Utilize SMN
> index 0 for driver probe").
> 
> The reason for the regression is that before this commit the SMN
> communication was hardcoded, but after amd_smn_read() is used which
> relies upon the misc PCI ID used by DF function 3 being included in
> a table.  The ID was missing for model 78h, so this meant that the
> amd_smn_read() wouldn't work.
> 
> Add the missing ID into amd_nb, restoring s2idle on this system.

Is there a long-term solution for this that will not require adding
new IDs every time new hardware comes out?

drivers/platform/x86/amd/pmc.c already matches ACPI IDs; maybe there's
some way for the platform to provide the information you need via
ACPI or something?

Bjorn