Re: [linux-pm] [patch update 2 fix] PM: Introduce core framework for run-time PM of I/O devices

Rafael J. Wysocki
2009-06-22T15:33:21Z

On Monday 22 June 2009, Arjan van de Ven wrote:
> On Mon, 22 Jun 2009 15:20:43 +0900
> Magnus Damm <magnus.damm@gmail.com> wrote:
>
> > On Sat, Jun 20, 2009 at 11:30 PM, Alan
> > Stern<stern@rowland.harvard.edu> wrote:
> > > Some more thoughts...
> > >
> > > Magnus, you might have some insights here. It occurred to me that
> > > some devices can switch power levels very quickly, and the drivers
> > > might therefore want the runtime suspend and resume methods to be
> > > called as soon as possible, even in interrupt context.
> >
> > I'd like to call pm_request_suspend() from interrupt context. I don't
>
> there are some really strong reasons to at least be able to call the
> resume function from an interrupt handler.... shared interrupts are one
> of them.

Yes. But that requires your hardware to be able to wake up fast enough, so I
think we can introduce pm_runtime_resume_atomic() and
pm_runtime_suspend_atomic() to be used with the devices that can do that, as
proposed by Alan.

Surely not all devices can do it, though.

Best,
Rafael