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Re: [PATCH] PM / wakeirq: report wakeup events in dedicated wake-IRQs

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On Thu, Nov 10, 2016 at 10:13:55AM -0800, Dmitry Torokhov wrote:
> On Thu, Nov 10, 2016 at 10:07 AM, Brian Norris <briannorris@chromium.org> wrote:
> > It's important that user space can figure out what device woke the
> > system from suspend -- e.g., for debugging, or for implementing
> > conditional wake behavior. Dedicated wakeup IRQs don't currently do
> > that.
> >
> > Let's report the event (pm_wakeup_event()) and also allow drivers to
> > synchronize with these events in their resume path (hence, disable_irq()
> > instead of disable_irq_nosync()).
> 
> Hmm, dev_pm_disable_wake_irq() is called from
> rpm_suspend()/rpm_resume() that take dev->power.lock spinlock and
> disable interrupts. Dropping _nosync() feels dangerous.

Indeed. So how do you suggest we get sane wakeup reports? Every device
or bus that's going to use the dedicated wake APIs has to
synchronize_irq() [1] in their resume() routine? Seems like an odd
implementation detail to have to remember (and therefore most drivers
will get it wrong).

Brian

[1] Or maybe at least create a helper API that will extract the
dedicated wake IRQ number and do the synchronize_irq() for us, so
drivers don't have to stash this separately (or poke at
dev->power.wakeirq->irq) for no good reason.

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[PATCH] PM / wakeirq: report wakeup events in dedicated wake-IRQs Brian Norris <briannorris@chromium.org> - 2016-11-10 19:10 +0100
  Re: [PATCH] PM / wakeirq: report wakeup events in dedicated wake-IRQs Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2016-11-10 19:20 +0100
    Re: [PATCH] PM / wakeirq: report wakeup events in dedicated wake-IRQs Brian Norris <briannorris@chromium.org> - 2016-11-10 19:50 +0100
      Re: [PATCH] PM / wakeirq: report wakeup events in dedicated wake-IRQs Tony Lindgren <tony@atomide.com> - 2016-11-10 21:50 +0100
        Re: [PATCH] PM / wakeirq: report wakeup events in dedicated wake-IRQs Brian Norris <briannorris@chromium.org> - 2016-11-10 22:40 +0100
          Re: [PATCH] PM / wakeirq: report wakeup events in dedicated wake-IRQs Tony Lindgren <tony@atomide.com> - 2016-11-11 17:50 +0100
            Re: [PATCH] PM / wakeirq: report wakeup events in dedicated wake-IRQs Brian Norris <briannorris@chromium.org> - 2016-11-11 20:50 +0100
      Re: [PATCH] PM / wakeirq: report wakeup events in dedicated wake-IRQs "Rafael J. Wysocki" <rafael@kernel.org> - 2016-11-11 01:10 +0100
        Re: [PATCH] PM / wakeirq: report wakeup events in dedicated wake-IRQs Tony Lindgren <tony@atomide.com> - 2016-11-11 17:40 +0100
  Re: [PATCH] PM / wakeirq: report wakeup events in dedicated wake-IRQs Pavel Machek <pavel@ucw.cz> - 2016-11-10 22:00 +0100
    Re: [PATCH] PM / wakeirq: report wakeup events in dedicated wake-IRQs Brian Norris <briannorris@chromium.org> - 2016-11-10 22:50 +0100

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