Messages in this thread | | | Date | Thu, 5 Mar 2015 10:53:08 +0000 | From | Mark Rutland <> | Subject | Re: [PATCH v2 5/6] watchdog: at91sam9: request the irq with IRQF_NO_SUSPEND |
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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.
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