Re: [PATCH 1/5] introduce .wakeup_event ops

Shaohua Li
2009-08-24T01:50:46Z

On Fri, Aug 21, 2009 at 05:23:16PM +0800, Matthew Garrett wrote:
> On Fri, Aug 21, 2009 at 02:33:50PM +0800, Shaohua Li wrote:
> > On Thu, Aug 20, 2009 at 03:40:51PM +0800, Matthew Garrett wrote:
> > > _L0B will only be triggered if a PME is generated, so we'll be able to
> > > determine which device generated the wakeup by looking at the PME
> > > registers.
> > Right, but the event is sent to a bridge. The devices under the bridge invoke
> > wakeup event, not the bridge itself. So you must scan all devices under the
> > bridge to check which device has its PME registers set.
> > So the bridge case isn't what you said (notification always sent to a specific
> > device which invokes the wakeup event)
>
> Yes, but that's fine because the PME state tells us exactly which device
> caused the wakeup. We'll never get a bus notification if the wakeup is
> triggered by UHCI on Intel.
Hmm, but here what we are talking about is if notification is always sent to the device
which invokes wakeup event.
I pointed out this isn't true because BIOS might sent notification to a pci bridge and
OS should scan devices under the bridge to check which devices invokes it by looking at
PME state. Looks you are talking about other things.

Thanks,
Shaohua