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

[Matthew Garrett <mjg59@srcf.ucam.org>]

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.

-- 
Matthew Garrett | mjg59@srcf.ucam.org