Re: [PATCH 4/6] PM / sleep: Make it possible to quiesce timers during suspend-to-idle

Rafael J. Wysocki
2015-02-12T16:19:37Z

On Thursday, February 12, 2015 02:24:47 PM Peter Zijlstra wrote:
> On Wed, Feb 11, 2015 at 05:03:44AM +0100, Rafael J. Wysocki wrote:
> > Index: linux-pm/include/linux/cpuidle.h
> > ===================================================================
> > --- linux-pm.orig/include/linux/cpuidle.h
> > +++ linux-pm/include/linux/cpuidle.h
> > @@ -50,6 +50,10 @@ struct cpuidle_state {
> > int index);
> >
> > int (*enter_dead) (struct cpuidle_device *dev, int index);
>
> Do we want a comment here describing that enter_freeze() must not
> re-enable interrupts _ever_?
>
> To help people who want to enable this on their platform.

Good point.

I'll update the patch later today.

> > +
> > + void (*enter_freeze) (struct cpuidle_device *dev,
> > + struct cpuidle_driver *drv,
> > + int index);
> > };
>
> > +static void enter_freeze_proper(struct cpuidle_driver *drv,
> > + struct cpuidle_device *dev, int index)
> > +{
> > + tick_freeze();
> > + /*
> > + * The state used here cannot be a "coupled" one, because the "coupled"
> > + * cpuidle mechanism enables interrupts and doing that with timekeeping
> > + * suspended is generally unsafe.
> > + */
> > + drv->states[index].enter_freeze(dev, drv, index);
>
> WARN_ON(!irqs_disabled());
>
> To go along with the comment and catch fail?

Yeah, will do.