linux-kernel - Re: [PATCH v1 4/9] PM: Move pm_runtime_force_suspend/resume() under CONFIG_PM

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Message-ID: <CAPDyKFoW5ag69LBnxvP5oGH1VAErBn17CAOzh=MX2toxAHwLxA@mail.gmail.com>
Date: Thu, 26 Jun 2025 12:04:33 +0200
From: Ulf Hansson <ulf.hansson@...aro.org>
To: "Rafael J. Wysocki" <rafael@...nel.org>
Cc: "Rafael J. Wysocki" <rjw@...ysocki.net>, Linux PM <linux-pm@...r.kernel.org>, 
	LKML <linux-kernel@...r.kernel.org>, Linux ACPI <linux-acpi@...r.kernel.org>, 
	Linux PCI <linux-pci@...r.kernel.org>, 
	Mika Westerberg <mika.westerberg@...ux.intel.com>
Subject: Re: [PATCH v1 4/9] PM: Move pm_runtime_force_suspend/resume() under CONFIG_PM_SLEEP

On Thu, 26 Jun 2025 at 11:41, Rafael J. Wysocki <rafael@...nel.org> wrote:
>
> On Thu, Jun 26, 2025 at 11:38 AM Ulf Hansson <ulf.hansson@...aro.org> wrote:
> >
> > On Wed, 25 Jun 2025 at 21:25, Rafael J. Wysocki <rjw@...ysocki.net> wrote:
> > >
> > > From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> > >
> > > Since pm_runtime_force_suspend/resume() and pm_runtime_need_not_resume()
> > > are only used during system-wide PM transitions, there is no reason to
> > > compile them in if CONFIG_PM_SLEEP is unset.
> > >
> > > Accordingly, move them all under CONFIG_PM_SLEEP and make the static
> > > inline stubs for pm_runtime_force_suspend/resume() return an error
> > > to indicate that they should not be used outside CONFIG_PM_SLEEP.
> > >
> >
> > Just realized that there seems to be some drivers that actually make
> > use of pm_runtime_force_suspend() from their ->remove() callbacks.
> >
> > To not break them, we probably need to leave this code to stay under CONFIG_PM.
>
> OK, pm_runtime_force_suspend() need not be under CONFIG_PM_SLEEP.
> That's not the case for the other two functions though AFAICS.

Right, but maybe better to keep them to avoid confusion? At least the
corresponding flag is needed.

Kind regards
Uffe

>
> > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> > > ---
> > >  drivers/base/power/runtime.c |    4 ++++
> > >  include/linux/pm_runtime.h   |   20 ++++++++++++++------
> > >  2 files changed, 18 insertions(+), 6 deletions(-)
> > >
> > > --- a/drivers/base/power/runtime.c
> > > +++ b/drivers/base/power/runtime.c
> > > @@ -1941,6 +1941,8 @@
> > >         pm_request_idle(link->supplier);
> > >  }
> > >
> > > +#ifdef CONFIG_PM_SLEEP
> > > +
> > >  bool pm_runtime_need_not_resume(struct device *dev)
> > >  {
> > >         return atomic_read(&dev->power.usage_count) <= 1 &&
> > > @@ -2063,3 +2065,5 @@
> > >         return ret;
> > >  }
> > >  EXPORT_SYMBOL_GPL(pm_runtime_force_resume);
> > > +
> > > +#endif /* CONFIG_PM_SLEEP */
> > > --- a/include/linux/pm_runtime.h
> > > +++ b/include/linux/pm_runtime.h
> > > @@ -66,9 +66,6 @@
> > >
> > >  extern int pm_generic_runtime_suspend(struct device *dev);
> > >  extern int pm_generic_runtime_resume(struct device *dev);
> > > -extern bool pm_runtime_need_not_resume(struct device *dev);
> > > -extern int pm_runtime_force_suspend(struct device *dev);
> > > -extern int pm_runtime_force_resume(struct device *dev);
> > >
> > >  extern int __pm_runtime_idle(struct device *dev, int rpmflags);
> > >  extern int __pm_runtime_suspend(struct device *dev, int rpmflags);
> > > @@ -257,9 +254,6 @@
> > >
> > >  static inline int pm_generic_runtime_suspend(struct device *dev) { return 0; }
> > >  static inline int pm_generic_runtime_resume(struct device *dev) { return 0; }
> > > -static inline bool pm_runtime_need_not_resume(struct device *dev) {return true; }
> > > -static inline int pm_runtime_force_suspend(struct device *dev) { return 0; }
> > > -static inline int pm_runtime_force_resume(struct device *dev) { return 0; }
> > >
> > >  static inline int __pm_runtime_idle(struct device *dev, int rpmflags)
> > >  {
> > > @@ -330,6 +324,20 @@
> > >
> > >  #endif /* !CONFIG_PM */
> > >
> > > +#ifdef CONFIG_PM_SLEEP
> > > +
> > > +extern bool pm_runtime_need_not_resume(struct device *dev);
> > > +extern int pm_runtime_force_suspend(struct device *dev);
> > > +extern int pm_runtime_force_resume(struct device *dev);
> > > +
> > > +#else /* !CONFIG_PM_SLEEP */
> > > +
> > > +static inline bool pm_runtime_need_not_resume(struct device *dev) {return true; }
> > > +static inline int pm_runtime_force_suspend(struct device *dev) { return -ENXIO; }
> > > +static inline int pm_runtime_force_resume(struct device *dev) { return -ENXIO; }
> > > +
> > > +#endif /* CONFIG_PM_SLEEP */
> > > +
> > >  /**
> > >   * pm_runtime_idle - Conditionally set up autosuspend of a device or suspend it.
> > >   * @dev: Target device.
> > >
> > >
> > >
> >