Re: [PATCH 1/4] PCI / ACPI: Identify external PCI devices

[Lorenzo Pieralisi]

On Tue, Nov 13, 2018 at 01:27:00PM +0200, Mika Westerberg wrote:

[...]

> > To be frank the concept (and Microsoft _DSD bindings) seems a bit vague
> > and not thoroughly defined and I would question its detection at
> > PCI/ACPI core level, I would hope this can be clarified at ACPI
> > specification level, at least.
> 
> I guess that is the way they envision to use _DSD. Instead of having
> single UUID that covers all properties (like what we have with device
> properties) they have one UUID per property "class". I certainly hope we
> don't need to keep extending prp_guids[] array each time they invent
> another "class" of properties.

It is even worse than that. This is a unilateral/obscure change that
won't be part of ACPI specifications (I guess it was easier to add a
UUID than add this to the ACPI specifications through the AWSG) but it
is still supposed to be applicable to ACPI PCI bindings on any
platforms/arches; this way of adding bindings does not work and it
has to be rectified.

Lorenzo