Re: [PATCH v2 5/6] watchdog: at91sam9: request the irq with IRQF_NO_SUSPEND

Mark Rutland
2015-03-05T10:58:00Z

[...]

> > > err = request_irq(wdt->irq, wdt_interrupt,
> > > - IRQF_SHARED | IRQF_IRQPOLL,
> > > + IRQF_SHARED | IRQF_IRQPOLL |
> > > + IRQF_NO_SUSPEND,
> >
> > I'm a little confused by this. What happens if the watchdog fires when
> > we're actually in the suspended state (when IRQF_NO_SUSPEND interrupts
> > aren't guaranteed to be delivered).
>
> Why wouldn't they be delivered?
>
> If that's suspend-to-idle, we'll handle them normally. If that's full suspend,
> they may not be handled at the last stage (when we run on one CPU with interrupts
> off), but that was the case before the wakeup interrupts rework already and I'd
> expect it to be taken into account somehow in the existing code (or if it isn't
> taken into account, we have a bug, but it is not related to this series).

There's no enable_irq_wake(wdt->irq), and I was under the impression this
is for full suspend.

I agree that if problematic, it's an existing bug. Given Boris's
comments in the other thread this may just a minor semantic issue w.r.t.
IRQF_NO_SUSPEND vs IRQF_COND_SUSPEND.

Thanks,
Mark.