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

Mark Rutland
2015-03-05T10:53:08Z

Hi Boris,

I'd missed the fact that this was for SW watchdog as opposed to HW
watchdog, which may explain my confusion.

[...]

> > > 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).
>
> It reboot the system.

Is the timer we use to ping the watchdog guaranted to result in a wakeup
before an interrupt will be triggered? If so, then I think we're ok.

If not, then don't we need to clear a potentially pending watchdog irq
at resume time so at to not immediately reboot the machine? I couldn't
see any logic to that effect in the driver.

Regardless, if the only reason we care about taking the interrupt during
the suspend/resume phases is due to the timer sharing the IRQ, then
shouldn't we be using IRQF_COND_SUSPEND?

Thanks,
Mark.