Messages in this thread | | | Date | Tue, 8 Jun 2021 10:49:05 -0400 | From | Alan Stern <> | Subject | Re: [PATCH v2 3/3] PM: runtime: Clarify documentation when callbacks are unassigned |
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On Tue, Jun 08, 2021 at 04:30:48PM +0200, Ulf Hansson wrote: > On Tue, 8 Jun 2021 at 16:23, Alan Stern <stern@rowland.harvard.edu> wrote: > > > > On Tue, Jun 08, 2021 at 11:02:50AM +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 v2: > > > - Added a new patch for the updating the docs, as pointed out by Alan. > > > > > > --- > > > Documentation/power/runtime_pm.rst | 8 ++++++++ > > > 1 file changed, 8 insertions(+) > > > > > > diff --git a/Documentation/power/runtime_pm.rst b/Documentation/power/runtime_pm.rst > > > index 18ae21bf7f92..3d09c9fd450d 100644 > > > --- a/Documentation/power/runtime_pm.rst > > > +++ b/Documentation/power/runtime_pm.rst > > > @@ -827,6 +827,14 @@ 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
More than 80 chars.
> > > +pm_runtime_no_callbacks() for their devices. This could be because a subset of
More than 80 chars.
> > > +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 manged
s/manged/managed/
> > > +through a supplier device link. For these reasons and to avoid boilerplate code
More than 80 chars.
> > > +in subsystems/drivers, the PM core allows runtime PM callbacks to be > > > +unassigned. > > > + > > > > You should also mention that if a callback pointer is NULL, the > > runtime PM core will act as though there was a callback and it > > returned 0. That's an important consideration. > > Good point, let me add it. > > I send a new version of $subject patch, unless Rafael is happy to do > the amending when/if applying? > > > > > Also, notice that this file was carefully edited to make sure that > > none of the lines exceed 80 characters. Your new addition should > > be the same. > > Absolutely, but it should be okay already, no?
See above.
Alan
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