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

Linus Torvalds
2009-02-25T16:20:43Z

On Wed, 25 Feb 2009, Alan Stern wrote:

> On Tue, 24 Feb 2009, Rafael J. Wysocki wrote:
>
> > I think the most important source of level triggered interrupts are PCI
> > devices, so perhaps we can make the PCI PM core use bit 10 of the PCI Device
> > Control register to prevent devices from generating INTx after the drivers'
> > suspend routines have been executed?
>
> I wish that were true. As I recall, the original PCI specification did
> not define this bit, and older PCI devices don't support it. So you
> can't count on being able to supress interrupt generation this way.

It's definitely a new feature. In fact, I think even the current one makes
it optional, so even for "new" devices it's very unclear how many of them
actually support that bit.

Linus