linux-kernel - Re: [RFC v0 2/9] suspend: Add getter function to report if freezing is active

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Message-ID: <1683655.HLd9k04Slu@vostro.rjw.lan>
Date:	Sat, 05 Sep 2015 04:11:16 +0200
From:	"Rafael J. Wysocki" <rjw@...ysocki.net>
To:	Daniel Wagner <daniel.wagner@...-carit.de>
Cc:	linux-kernel@...r.kernel.org, Len Brown <len.brown@...el.com>,
	Pavel Machek <pavel@....cz>, linux-pm@...r.kernel.org
Subject: Re: [RFC v0 2/9] suspend: Add getter function to report if freezing is active

On Friday, September 04, 2015 03:34:55 PM Daniel Wagner wrote:
> Instead encode the FREEZE state via the CPU state we allow the
> interesting subsystems (MCE, microcode) to query the power
> subsystem directly.

A use case, please.

> Most notifiers are not interested at all
> in this information so rather have explicit calls to freeze_active()
> instead adding complexity to the rest of the users of the CPU
> notifiers.

Why does it has anything to do with CPU notifiers?  We don't offline
CPUs for suspend-to-idle.


> Signed-off-by: Daniel Wagner <daniel.wagner@...-carit.de>
> Cc: "Rafael J. Wysocki" <rjw@...ysocki.net>
> Cc: Len Brown <len.brown@...el.com>
> Cc: Pavel Machek <pavel@....cz>
> Cc: linux-pm@...r.kernel.org
> Cc: linux-kernel@...r.kernel.org
> ---
>  include/linux/suspend.h | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/include/linux/suspend.h b/include/linux/suspend.h
> index 5efe743..5e15ade 100644
> --- a/include/linux/suspend.h
> +++ b/include/linux/suspend.h
> @@ -216,6 +216,11 @@ static inline bool idle_should_freeze(void)
>  	return unlikely(suspend_freeze_state == FREEZE_STATE_ENTER);
>  }
>  
> +static inline bool freeze_active(void)
> +{
> +	return unlikely(suspend_freeze_state != FREEZE_STATE_NONE);
> +}
> +
>  extern void freeze_set_ops(const struct platform_freeze_ops *ops);
>  extern void freeze_wake(void);
>  
> @@ -244,6 +249,7 @@ extern int pm_suspend(suspend_state_t state);
>  static inline void suspend_set_ops(const struct platform_suspend_ops *ops) {}
>  static inline int pm_suspend(suspend_state_t state) { return -ENOSYS; }
>  static inline bool idle_should_freeze(void) { return false; }
> +static inline bool freeze_active(void) { return false; }
>  static inline void freeze_set_ops(const struct platform_freeze_ops *ops) {}
>  static inline void freeze_wake(void) {}
>  #endif /* !CONFIG_SUSPEND */
> 

-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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