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

Alan Stern
2016-04-03T18:27:30Z

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@kernel.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@rowland.harvard.edu>