Re: PME# for add-on cards

Jesse Barnes
2009-08-24T19:12:39Z

On Mon, 24 Aug 2009 20:39:07 +0200
"Rafael J. Wysocki" <rjw@sisk.pl> wrote:

> On Monday 24 August 2009, Matthew Garrett wrote:
> > On Mon, Aug 24, 2009 at 01:12:39AM +0200, Rafael J. Wysocki wrote:
> >
> > > After some debugging it turned out that PCI0 is the PCI host
> > > bridge (no-bus:pci0000:00), so apparently echoing PCI0
> > > to /proc/acpi/wakeup causes a wake-up GPE to be set up for the
> > > host bridge which triggers wake-up once eth0 signals PME#.
> >
> > Mm. That sounds entirely plausible. If it were a built-in card then
> > the DSDT would provide that GPE, but as an add-in...
> >
> > > First, I wonder if that's the case in general (anybody knows?).
> > > Second, if that is the case, would it be a good idea to set up
> > > the host bridge wake-up GPE by default?
> >
> > I'd expect this to be the case in general, yes. Systems that work
> > without this probably have the BIOS enable it themselves on
> > suspend. I suspect we'll have to set it to make sure.
>
> OK, Matthew, Alan, thanks for your opinions.
>
> I'll try to implement this, then.

I think that's the best approach. The only risk that I can see
immediately is that we'll expose ourselves to add-in cards with flakey
PME# signals. We can worry about that when/if we see it though.

Thanks,
--
Jesse Barnes, Intel Open Source Technology Center