linux-kernel - Re: [PATCH 1/6] Hibernation: Introduce system_entering

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Message-ID: <20090119212428.GB6194@nowhere>
Date:	Mon, 19 Jan 2009 22:25:20 +0100
From:	Frederic Weisbecker <fweisbec@...il.com>
To:	"Rafael J. Wysocki" <rjw@...k.pl>
Cc:	Jeff Garzik <jeff@...zik.org>, Frans Pop <elendil@...net.nl>,
	tj@...nel.org, akpm@...ux-foundation.org,
	torvalds@...ux-foundation.org, linux-ide@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/6] Hibernation: Introduce system_entering_hibernation

On Mon, Jan 19, 2009 at 08:54:54PM +0100, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rjw@...k.pl>
> 
> Introduce boolean function system_entering_hibernation() returning
> 'true' during the last phase of hibernation, in which devices are
> being put into low power states and the sleep state (for example,
> ACPI S4) is finally entered.
> 
> Some device drivers need such a function to check if the system is
> in the final phase of hibernation.  In particular, some SATA drivers
> are going to use it for blacklisting systems in which the disks
> should not be spun down during the last phase of hibernation (the
> BIOS will do that anyway).
>

Hi Rafael,

Why not using the power event notifier?

Frederic.

 
> Signed-off-by: Rafael J. Wysocki <rjw@...k.pl>
> ---
>  include/linux/suspend.h |    2 ++
>  kernel/power/disk.c     |   10 ++++++++++
>  2 files changed, 12 insertions(+)
> 
> Index: linux-2.6/include/linux/suspend.h
> ===================================================================
> --- linux-2.6.orig/include/linux/suspend.h
> +++ linux-2.6/include/linux/suspend.h
> @@ -237,6 +237,7 @@ extern int hibernate_nvs_alloc(void);
>  extern void hibernate_nvs_free(void);
>  extern void hibernate_nvs_save(void);
>  extern void hibernate_nvs_restore(void);
> +extern bool system_entering_hibernation(void);
>  #else /* CONFIG_HIBERNATION */
>  static inline int swsusp_page_is_forbidden(struct page *p) { return 0; }
>  static inline void swsusp_set_page_free(struct page *p) {}
> @@ -252,6 +253,7 @@ static inline int hibernate_nvs_alloc(vo
>  static inline void hibernate_nvs_free(void) {}
>  static inline void hibernate_nvs_save(void) {}
>  static inline void hibernate_nvs_restore(void) {}
> +static inline bool system_entering_hibernation(void) { return false; }
>  #endif /* CONFIG_HIBERNATION */
>  
>  #ifdef CONFIG_PM_SLEEP
> Index: linux-2.6/kernel/power/disk.c
> ===================================================================
> --- linux-2.6.orig/kernel/power/disk.c
> +++ linux-2.6/kernel/power/disk.c
> @@ -71,6 +71,14 @@ void hibernation_set_ops(struct platform
>  	mutex_unlock(&pm_mutex);
>  }
>  
> +static bool entering_platform_hibernation;
> +
> +bool system_entering_hibernation(void)
> +{
> +	return entering_platform_hibernation;
> +}
> +EXPORT_SYMBOL(system_entering_hibernation);
> +
>  #ifdef CONFIG_PM_DEBUG
>  static void hibernation_debug_sleep(void)
>  {
> @@ -411,6 +419,7 @@ int hibernation_platform_enter(void)
>  	if (error)
>  		goto Close;
>  
> +	entering_platform_hibernation = true;
>  	suspend_console();
>  	error = device_suspend(PMSG_HIBERNATE);
>  	if (error) {
> @@ -445,6 +454,7 @@ int hibernation_platform_enter(void)
>   Finish:
>  	hibernation_ops->finish();
>   Resume_devices:
> +	entering_platform_hibernation = false;
>  	device_resume(PMSG_RESTORE);
>  	resume_console();
>   Close:
> 
> --
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