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

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Message-ID: <CAJZ5v0h-9UnvhrQ7YaaYPG5CktwV-i+ZeqAri8OhJQb4TVp82w@mail.gmail.com>
Date: Thu, 26 Jun 2025 11:41:14 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Ulf Hansson <ulf.hansson@...aro.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, 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.

> > 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.
> >
> >
> >
>