Re: [RFC][PATCH 4/4] PCI/ACPI PM: Propagate wake-up enable for devices w/o ACPI support

Rafael J. Wysocki
2009-09-04T22:21:25Z

On Saturday 05 September 2009, Matthew Garrett wrote:
> On Sat, Sep 05, 2009 at 12:00:32AM +0200, Rafael J. Wysocki wrote:
> > > Yes, it's presumably the case that the PME event in the bridge is just
> > > tied to the root bridge in the chipset. Do we know what chipset this
> > > hardware is? For Intel, at least, GPE behaviour is defined in the
> > > chipset docs.
> >
> > One box is Intel, the other one is based on an ATI (pre-AMD) chipset, but
> > the design is similar in that respect.
>
> GPE 0xb will be the one generated by any Intel chipset whenever the
> external PCI PME# goes active. 0xd is the equivalent for chipset-level
> devices that don't have a GPE of their own. I can't see any way that a
> downstream bridge could reasonably generate a GPE, so I'd bet that it's
> using 0xb.

I agree. Which seems to me that at least for Intel chipsets the "propagation"
loop can be stopped as soon as we find the first device with ACPI wakeup
support, like in the patch I've just sent.

Thanks,
Rafael