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

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Message-ID: <CAKdAkRRWUWmGUFaD=95Zd=wZfqXcs47YXL335Y4A+VmhtdJFTA@mail.gmail.com>
Date:   Thu, 10 Nov 2016 10:13:55 -0800
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Brian Norris <briannorris@...omium.org>
Cc:     "Rafael J . Wysocki" <rjw@...ysocki.net>,
        Pavel Machek <pavel@....cz>, Len Brown <len.brown@...el.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        lkml <linux-kernel@...r.kernel.org>,
        Brian Norris <computersforpeace@...il.com>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        Tony Lindgren <tony@...mide.com>
Subject: Re: [PATCH] PM / wakeirq: report wakeup events in dedicated wake-IRQs

On Thu, Nov 10, 2016 at 10:07 AM, Brian Norris <briannorris@...omium.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.

>
> Signed-off-by: Brian Norris <briannorris@...omium.org>
> ---
>  drivers/base/power/wakeirq.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/base/power/wakeirq.c b/drivers/base/power/wakeirq.c
> index 0d77cd6fd8d1..c35b2db1194c 100644
> --- a/drivers/base/power/wakeirq.c
> +++ b/drivers/base/power/wakeirq.c
> @@ -139,6 +139,8 @@ static irqreturn_t handle_threaded_wake_irq(int irq, void *_wirq)
>         struct wake_irq *wirq = _wirq;
>         int res;
>
> +       pm_wakeup_event(wirq->dev, 0);
> +
>         /* We don't want RPM_ASYNC or RPM_NOWAIT here */
>         res = pm_runtime_resume(wirq->dev);
>         if (res < 0)
> @@ -240,7 +242,7 @@ void dev_pm_disable_wake_irq(struct device *dev)
>         struct wake_irq *wirq = dev->power.wakeirq;
>
>         if (wirq && wirq->dedicated_irq)
> -               disable_irq_nosync(wirq->irq);
> +               disable_irq(wirq->irq);
>  }
>  EXPORT_SYMBOL_GPL(dev_pm_disable_wake_irq);
>
> --
> 2.8.0.rc3.226.g39d4020
>



-- 
Dmitry