linux-kernel - Re: [PATCH v1 2/3] PM / sleep: try to runtime suspend for direct complete

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Date:	Tue, 1 Mar 2016 21:41:33 +0100
From:	Ulf Hansson <ulf.hansson@...aro.org>
To:	Derek Basehore <dbasehore@...omium.org>
Cc:	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
	"Rafael J . Wysocki" <rjw@...ysocki.net>,
	Len Brown <len.brown@...el.com>, Pavel Machek <pavel@....cz>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"James E . J . Bottomley" <JBottomley@...n.com>,
	"Martin K . Petersen" <martin.petersen@...cle.com>,
	linux-scsi <linux-scsi@...r.kernel.org>
Subject: Re: [PATCH v1 2/3] PM / sleep: try to runtime suspend for direct complete

On 25 February 2016 at 01:11, Derek Basehore <dbasehore@...omium.org> wrote:
> This tries to runtime suspend devices that are still active for direct
> complete. This is for cases such as autosuspend delays which leaves
> devices able to runtime suspend but still active. It's beneficial in
> this case to runtime suspend the device to take advantage of direct
> complete when possible.

Unfortunate this doesn't work. In the device_prepare() phase the PM
core prevents runtime suspend via a call to pm_runtime_get_noresume().

Kind regards
Uffe

>
> Signed-off-by: Derek Basehore <dbasehore@...omium.org>
> Reviewed-by: Eric Caruso <ejcaruso@...omium.org>
> ---
>  drivers/base/power/main.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
> index e0017d9..9693032 100644
> --- a/drivers/base/power/main.c
> +++ b/drivers/base/power/main.c
> @@ -1380,7 +1380,12 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
>                 goto Complete;
>
>         if (dev->power.direct_complete) {
> -               if (pm_runtime_status_suspended(dev)) {
> +               /*
> +                * Check if we're runtime suspended. If not, try to runtime
> +                * suspend for autosuspend cases.
> +                */
> +               if (pm_runtime_status_suspended(dev) ||
> +                   !pm_runtime_suspend(dev)) {
>                         pm_runtime_disable(dev);
>                         if (pm_runtime_status_suspended(dev))
>                                 goto Complete;
> --
> 2.7.0.rc3.207.g0ac5344
>