Re: [RFC][PATCH 2/2] PM: Rework handling of interrupts during suspend-resume

Rafael J. Wysocki
2009-02-24T23:07:11Z

On Tuesday 24 February 2009, Linus Torvalds wrote:
>
> On Tue, 24 Feb 2009, Rafael J. Wysocki wrote:
> >
> > > The only safe way on x86 to shutdown a level triggered ioapic irq
> > > outside of irq context is for the driver to program the hardware to
> > > not generate an irq.
> >
> > Well, that changes things quite a bit, because it means we can't change the
> > suspend-resume sequence in a way we thought we could without fixing all
> > drivers first, but this is exactly what we'd like to avoid by changing the
> > core.
>
> Calling "disable_irq()" is perfectly fine.
>
> What is not possible on that broken IO-APIC (among other things) is to
> actually turn the interrupts off at the apic (ie the whole ->shutdown()
> thing). But that's not what we even want to do. What we care about is
> just disabling the interrupt from a drievr perspective.
>
> IOW, the patches I have seen are fine, and all the comments from Eric are
> just confusion about what we want done.

Ah, OK. Thanks for the explanation, I got confused too.

> WE DO NOT WANT TO TURN OFF THE IO-APIC. That may or may happen later, but
> that's totally unrelated to this whole "suspend_device_irq()" thing.

Yeah.

Rafael