linux-kernel - Re: [PATCH v1 2/3] PM: runtime: Introduce pm_runtime

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Message-ID: <CAPDyKFpp1iuBXZB-T2=hhTND4Z63s7kJfaXWuiKTu1rrqMGc_Q@mail.gmail.com>
Date: Tue, 18 Feb 2025 13:49:34 +0100
From: Ulf Hansson <ulf.hansson@...aro.org>
To: "Rafael J. Wysocki" <rjw@...ysocki.net>
Cc: Linux PM <linux-pm@...r.kernel.org>, LKML <linux-kernel@...r.kernel.org>, 
	Alan Stern <stern@...land.harvard.edu>, Bjorn Helgaas <helgaas@...nel.org>, 
	Linux PCI <linux-pci@...r.kernel.org>, Johan Hovold <johan@...nel.org>, 
	Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>, Jon Hunter <jonathanh@...dia.com>, 
	Linux ACPI <linux-acpi@...r.kernel.org>, 
	Mika Westerberg <mika.westerberg@...ux.intel.com>, 
	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Subject: Re: [PATCH v1 2/3] PM: runtime: Introduce pm_runtime_blocked()

On Mon, 17 Feb 2025 at 21:20, Rafael J. Wysocki <rjw@...ysocki.net> wrote:
>
> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
>
> Introduce a new helper function called pm_runtime_blocked() for
> checking the power.last_status value indicating whether or not the
> enabling of runtime PM for the given device has been blocked (which
> happens in the "prepare" phase of system-wide suspend if runtime
> PM is disabled for the given device at that point and has never
> been enabled so far).
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

Reviewed-by: Ulf Hansson <ulf.hansson@...aro.org>

Kind regards
Uffe


> ---
>  drivers/base/power/runtime.c |   17 +++++++++++++++++
>  include/linux/pm_runtime.h   |    2 ++
>  2 files changed, 19 insertions(+)
>
> --- a/drivers/base/power/runtime.c
> +++ b/drivers/base/power/runtime.c
> @@ -1555,6 +1555,23 @@
>  }
>  EXPORT_SYMBOL_GPL(pm_runtime_enable);
>
> +bool pm_runtime_blocked(struct device *dev)
> +{
> +       bool ret;
> +
> +       /*
> +        * dev->power.last_status is a bit field, so in case it is updated via
> +        * RMW, read it under the spin lock.
> +        */
> +       spin_lock_irq(&dev->power.lock);
> +
> +       ret = dev->power.last_status == RPM_BLOCKED;
> +
> +       spin_unlock_irq(&dev->power.lock);
> +
> +       return ret;
> +}
> +
>  static void pm_runtime_disable_action(void *data)
>  {
>         pm_runtime_dont_use_autosuspend(data);
> --- a/include/linux/pm_runtime.h
> +++ b/include/linux/pm_runtime.h
> @@ -81,6 +81,7 @@
>  extern void pm_runtime_unblock(struct device *dev);
>  extern void pm_runtime_enable(struct device *dev);
>  extern void __pm_runtime_disable(struct device *dev, bool regular);
> +extern bool pm_runtime_blocked(struct device *dev);
>  extern void pm_runtime_allow(struct device *dev);
>  extern void pm_runtime_forbid(struct device *dev);
>  extern void pm_runtime_no_callbacks(struct device *dev);
> @@ -277,6 +278,7 @@
>  static inline void pm_runtime_unblock(struct device *dev) {}
>  static inline void pm_runtime_enable(struct device *dev) {}
>  static inline void __pm_runtime_disable(struct device *dev, bool c) {}
> +static inline bool pm_runtime_blocked(struct device *dev) { return true; }
>  static inline void pm_runtime_allow(struct device *dev) {}
>  static inline void pm_runtime_forbid(struct device *dev) {}
>
>
>
>