| Message ID | 20210609100610.97830-1-ulf.hansson@linaro.org |
|---|---|
| State | Accepted |
| Commit | 4ec4f059088b48585c337328e05fa930c64d1ba8 |
| Headers | show |
| Series | None | expand |
On Wed, Jun 09, 2021 at 12:06:10PM +0200, Ulf Hansson wrote: > Recent changes to the PM core allows ->runtime_suspend|resume callbacks to > be unassigned. > > In the earlier behaviour the PM core would return -ENOSYS, when trying to > runtime resume a device, for example. Let's update the documentation to > clarify this. > > Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> > --- > > Changes in v4: > - This time, really, fix spelling and further clarified the behaviour, > according to comments from Alan. > > --- > Documentation/power/runtime_pm.rst | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/Documentation/power/runtime_pm.rst b/Documentation/power/runtime_pm.rst > index 18ae21bf7f92..8a0a43811e3a 100644 > --- a/Documentation/power/runtime_pm.rst > +++ b/Documentation/power/runtime_pm.rst > @@ -827,6 +827,15 @@ or driver about runtime power changes. Instead, the driver for the device's > parent must take responsibility for telling the device's driver when the > parent's power state changes. > > +Note that, in some cases it may not be desirable for subsystems/drivers to call > +pm_runtime_no_callbacks() for their devices. This could be because a subset of > +the runtime PM callbacks needs to be implemented, a platform dependent PM > +domain could get attached to the device or that the device is power managed > +through a supplier device link. For these reasons and to avoid boilerplate code > +in subsystems/drivers, the PM core allows runtime PM callbacks to be > +unassigned. More precisely, if a callback pointer is NULL, the PM core will act > +as though there was a callback and it returned 0. > + > 9. Autosuspend, or automatically-delayed suspends > ================================================= Acked-by: Alan Stern <stern@rowland.harvard.edu> I don't know what happened before. Maybe the terminal window got resized without me noticing, so the lines looked too long when they actually weren't. Alan Stern
On Wed, Jun 9, 2021 at 4:16 PM Alan Stern <stern@rowland.harvard.edu> wrote: > > On Wed, Jun 09, 2021 at 12:06:10PM +0200, Ulf Hansson wrote: > > Recent changes to the PM core allows ->runtime_suspend|resume callbacks to > > be unassigned. > > > > In the earlier behaviour the PM core would return -ENOSYS, when trying to > > runtime resume a device, for example. Let's update the documentation to > > clarify this. > > > > Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> > > --- > > > > Changes in v4: > > - This time, really, fix spelling and further clarified the behaviour, > > according to comments from Alan. > > > > --- > > Documentation/power/runtime_pm.rst | 9 +++++++++ > > 1 file changed, 9 insertions(+) > > > > diff --git a/Documentation/power/runtime_pm.rst b/Documentation/power/runtime_pm.rst > > index 18ae21bf7f92..8a0a43811e3a 100644 > > --- a/Documentation/power/runtime_pm.rst > > +++ b/Documentation/power/runtime_pm.rst > > @@ -827,6 +827,15 @@ or driver about runtime power changes. Instead, the driver for the device's > > parent must take responsibility for telling the device's driver when the > > parent's power state changes. > > > > +Note that, in some cases it may not be desirable for subsystems/drivers to call > > +pm_runtime_no_callbacks() for their devices. This could be because a subset of > > +the runtime PM callbacks needs to be implemented, a platform dependent PM > > +domain could get attached to the device or that the device is power managed > > +through a supplier device link. For these reasons and to avoid boilerplate code > > +in subsystems/drivers, the PM core allows runtime PM callbacks to be > > +unassigned. More precisely, if a callback pointer is NULL, the PM core will act > > +as though there was a callback and it returned 0. > > + > > 9. Autosuspend, or automatically-delayed suspends > > ================================================= > > Acked-by: Alan Stern <stern@rowland.harvard.edu> Applied as 5.14 material along with the [1-2/3] from this series. Thanks!
diff --git a/Documentation/power/runtime_pm.rst b/Documentation/power/runtime_pm.rst index 18ae21bf7f92..8a0a43811e3a 100644 --- a/Documentation/power/runtime_pm.rst +++ b/Documentation/power/runtime_pm.rst @@ -827,6 +827,15 @@ or driver about runtime power changes. Instead, the driver for the device's parent must take responsibility for telling the device's driver when the parent's power state changes. +Note that, in some cases it may not be desirable for subsystems/drivers to call +pm_runtime_no_callbacks() for their devices. This could be because a subset of +the runtime PM callbacks needs to be implemented, a platform dependent PM +domain could get attached to the device or that the device is power managed +through a supplier device link. For these reasons and to avoid boilerplate code +in subsystems/drivers, the PM core allows runtime PM callbacks to be +unassigned. More precisely, if a callback pointer is NULL, the PM core will act +as though there was a callback and it returned 0. + 9. Autosuspend, or automatically-delayed suspends =================================================
Recent changes to the PM core allows ->runtime_suspend|resume callbacks to be unassigned. In the earlier behaviour the PM core would return -ENOSYS, when trying to runtime resume a device, for example. Let's update the documentation to clarify this. Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> --- Changes in v4: - This time, really, fix spelling and further clarified the behaviour, according to comments from Alan. --- Documentation/power/runtime_pm.rst | 9 +++++++++ 1 file changed, 9 insertions(+) -- 2.25.1