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

[Mika Westerberg]

On Tue, Nov 13, 2018 at 11:45:36AM +0000, Lorenzo Pieralisi wrote:
> 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.

I agree.

For the existing property "classes" such as the one here I don't think
we can do anything. There are systems already with these included in
their ACPI tables.

I wonder if you have any objections regarding this patch?