[Skiboot] [PATCH] core/pci: Prefer ibm, slot-label when finding loc codes

[Stewart Smith]

"Oliver O'Halloran" <oohall at gmail.com> writes:
> On OpenPower systems the ibm,slot-label property is used to identify
> slots rather than the more verbose ibm,slot-location-code. The
> slot-label lookup is currently broken since it assumes that the
> ibm,slot-label is in the PCI device node rather than in the node of the
> device that provides the slot (e.g. root port or switch downstream
> port).
>
> This patch corrects the lookup code to search the parent node (and
> possibly it's grandparents), similar to how we search for
> ibm,slot-location-code.
>
> Fixes: 1c3baae4f2b3 ("hdata/iohub: Look for IOVPD on P9")
> Signed-off-by: Oliver O'Halloran <oohall at gmail.com>
> ---
> The Fixes: here is a bit mis-leading. It's been pretty much always
> broken, but we never really noticed because on most systems the
> slot-label and the slot-location-code are identical. 1c3baae4f2b3
> caused them to differ because the PHB's base location code was
> added to the DT which changes the generated slot-location-code to
> include the PHB location code.

So, I think this all ends up being what fixes the reported problem
(which, amusingly enough, we'd never actually hit in tests because of
tedious reasons involving GPUs and NVIDIA drivers)... I'm more convinced
by the internal testing than anything else tbh.

Merged to master as of ff960a77a192efd90d1be370c67c85cb82ce0e2e

-- 
Stewart Smith
OPAL Architect, IBM.