linux-kernel - Re: [PATCH v2] PM / runtime: Document steps for device removal

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Date:	Sun, 3 Apr 2016 14:27:27 -0400 (EDT)
From:	Alan Stern <stern@...land.harvard.edu>
To:	Krzysztof Kozlowski <krzk@...nel.org>
cc:	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Len Brown <len.brown@...el.com>, Pavel Machek <pavel@....cz>,
	<linux-pm@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] PM / runtime: Document steps for device removal

On Sun, 3 Apr 2016, Krzysztof Kozlowski wrote:

> Put a reminder that during device removal drivers should revert all PM
> runtime changes from the probe.
> 
> Signed-off-by: Krzysztof Kozlowski <krzk@...nel.org>
> 
> ---
> 
> Changes since v1:
> 1. Address Alan's comments.
> ---
>  Documentation/power/runtime_pm.txt | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/Documentation/power/runtime_pm.txt b/Documentation/power/runtime_pm.txt
> index 7328cf85236c..1fd1fbe9ce95 100644
> --- a/Documentation/power/runtime_pm.txt
> +++ b/Documentation/power/runtime_pm.txt
> @@ -586,6 +586,10 @@ drivers to make their ->remove() callbacks avoid races with runtime PM directly,
>  but also it allows of more flexibility in the handling of devices during the
>  removal of their drivers.
>  
> +Drivers in ->remove() callback should undo the runtime PM changes done
> +in ->probe(). Usually this means calling pm_runtime_disable(),
> +pm_runtime_dont_use_autosuspend() etc.
> +
>  The user space can effectively disallow the driver of the device to power manage
>  it at run time by changing the value of its /sys/devices/.../power/control
>  attribute to "on", which causes pm_runtime_forbid() to be called.  In principle,

Acked-by: Alan Stern <stern@...land.harvard.edu>