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

Rafael J. Wysocki
2009-09-04T21:59:28Z

On Friday 04 September 2009, Matthew Garrett wrote:
> On Fri, Sep 04, 2009 at 04:39:46PM +0200, Rafael J. Wysocki wrote:
>
> > Quite frankly, I'm not sure of that. It really depends on how PME# is routed
> > in given system. The spec permits routing it directly to the chipset as well
> > as routing it through bridges and I don't know if we can assume that the
> > first upstream device capable of generating wake-up events will handle it.
>
> The GPE block is going to be in the chipset, so unless the vendors have
> explicitly hooked up a link between the PME line from a bridge and the
> EC, we're presumably always going to get it from the chipset if at all.
>
> > That said, I think we can try returning from
> > acpi_pci_propagate_wakeup_enable() as soon as
> > acpi_pm_device_sleep_wake() returns 0 for current device. On the test systems
> > I have it won't make any difference, because the GPE is shared among the
> > root bridge and the first upstream bridge of the device in question.
>
> 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.

Thanks,
Rafael