2016-04-03 03:23:31

by Krzysztof Kozlowski

[permalink] [raw]
Subject: [PATCH v2] PM / runtime: Document steps for device removal

Put a reminder that during device removal drivers should revert all PM
runtime changes from the probe.

Signed-off-by: Krzysztof Kozlowski <[email protected]>

---

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,
--
2.1.4


2016-04-03 18:27:30

by Alan Stern

[permalink] [raw]
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 <[email protected]>
>
> ---
>
> 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 <[email protected]>

2016-04-06 23:32:15

by Rafael J. Wysocki

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

On Sunday, April 03, 2016 02:27:27 PM Alan Stern wrote:
> 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 <[email protected]>
> >
> > ---
> >
> > 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 <[email protected]>

Applied, thanks!