linux-kernel - Re: [PATCH] PM / Domains: Propagate start and restore errors during runtime resume

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Message-ID: <CAPDyKFp08Qy4Ui05f4gUhRPmEHZppfO1R=yPr0bq2FC=LCGcbQ@mail.gmail.com>
Date:	Fri, 4 Mar 2016 11:22:49 +0100
From:	Ulf Hansson <ulf.hansson@...aro.org>
To:	Laurent Pinchart <laurent.pinchart+renesas@...asonboard.com>
Cc:	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Kevin Hilman <khilman@...nel.org>
Subject: Re: [PATCH] PM / Domains: Propagate start and restore errors during
 runtime resume

On 2 March 2016 at 00:20, Laurent Pinchart
<laurent.pinchart+renesas@...asonboard.com> wrote:
> During runtime resume the return values of the start and restore steps
> are ignored. As a result drivers are not notified of runtime resume
> failures and can't propagate them up. Fix it by returning an error if
> either the start or restore step fails, and clean up properly in the
> error path.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@...asonboard.com>
> ---
>  drivers/base/power/domain.c | 20 ++++++++++++++++++--
>  1 file changed, 18 insertions(+), 2 deletions(-)
>
> This fixes an issue I've noticed with my driver's .runtime_resume() handler
> returning an error that was never propagated out of pm_runtime_get_sync().
>
> A second issue then appeared. The device .runtime_error field is set to the
> error code returned by my .runtime_resume() handler, but it never reset. Any
> subsequent try to resume the device fails with -EINVAL. I'm not sure what the
> right way to solve that is, advices are welcome.
>
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index 301b785f9f56..8cfcb8d6179b 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -485,8 +485,13 @@ static int pm_genpd_runtime_resume(struct device *dev)
>         if (timed && runtime_pm)
>                 time_start = ktime_get();
>
> -       genpd_start_dev(genpd, dev);
> -       genpd_restore_dev(genpd, dev);
> +       ret = genpd_start_dev(genpd, dev);
> +       if (ret)
> +               goto err_poweroff;
> +
> +       ret = genpd_restore_dev(genpd, dev);
> +       if (ret)
> +               goto err_stop;
>
>         /* Update resume latency value if the measured time exceeds it. */
>         if (timed && runtime_pm) {
> @@ -501,6 +506,17 @@ static int pm_genpd_runtime_resume(struct device *dev)
>         }
>
>         return 0;
> +
> +err_stop:
> +       genpd_stop_dev(genpd, dev);
> +err_poweroff:
> +       if (!dev->power.irq_safe) {

There's a helper function for this:
pm_runtime_is_irq_safe()

Perhaps, we can leave this as is here and then make a separate patch
converting all occurrences of the above into using the helper function
instead.

> +               mutex_lock(&genpd->lock);
> +               genpd_poweroff(genpd, 0);
> +               mutex_unlock(&genpd->lock);
> +       }
> +
> +       return ret;
>  }
>
>  static bool pd_ignore_unused;

Acked-by: Ulf Hansson <ulf.hansson@...aro.org>

Kind regards
Uffe