linux-kernel - Re: [PATCH] PM / sleep: fix unbalanced pm runtime disable in __device_suspend

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Date:	Thu, 19 May 2016 15:38:30 +0200
From:	"Rafael J. Wysocki" <rafael@...nel.org>
To:	Grygorii Strashko <grygorii.strashko@...com>
Cc:	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
	Len Brown <len.brown@...el.com>, Pavel Machek <pavel@....cz>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Kevin Hilman <khilman@...nel.org>,
	Ulf Hansson <ulf.hansson@...aro.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] PM / sleep: fix unbalanced pm runtime disable in __device_suspend_late()

On Fri, May 13, 2016 at 8:03 PM, Grygorii Strashko
<grygorii.strashko@...com> wrote:
> The PM runtime will be left disabled for the device if its .suspend_late()
> callback fails and async suspend is not allowed for this device. In
> this case device will not be added in dpm_late_early_list and
> dpm_resume_early() will ignore this device, as result PM runtime will
> be disabled for it forever (side effect: after 8 subsequent failures
> for the same device the PM runtime will be reenabled due to
> disable_depth overflow).
>
> Hence, re-enable PM runtime in __device_suspend_late() if
> .suspend_late() callback fails and async suspend is not allowed for
> this device.
>
> Signed-off-by: Grygorii Strashko <grygorii.strashko@...com>
> ---
>  drivers/base/power/main.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
> index 6e7c3cc..9b266e5 100644
> --- a/drivers/base/power/main.c
> +++ b/drivers/base/power/main.c
> @@ -1207,10 +1207,13 @@ static int __device_suspend_late(struct device *dev, pm_message_t state, bool as
>         }
>
>         error = dpm_run_callback(callback, dev, state, info);
> -       if (!error)
> +       if (!error) {
>                 dev->power.is_late_suspended = true;
> -       else
> +       } else {
>                 async_error = error;
> +               if (!is_async(dev))

Why is the is_async() check necessary here?

> +                       pm_runtime_enable(dev);
> +       }
>
>  Complete:
>         TRACE_SUSPEND(error);
> --