Re: [RFC][PATCH -mm 2/2] PM: Introduce suspend notifiers

[Pavel Machek <pavel@ucw.cz>]

Hi!


> Index: linux-2.6.21-rc6-mm1/Documentation/power/suspend-notifiers.txt
> ===================================================================
> --- /dev/null	1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6.21-rc6-mm1/Documentation/power/suspend-notifiers.txt	2007-04-21 23:24:50.000000000 +0200
> @@ -0,0 +1,41 @@
> +Suspend notifiers
> +	(C) 2007 Rafael J. Wysocki <rjw@sisk.pl>, GPL
> +
> +There are some operations that device drivers may want to carry out in their
> +.suspend() routines, but shouldn't, because they can cause a suspend to fail.
> +For example, a driver may want to allocate a substantial amount of memory
> +(like 50 MB) in .suspend(), but that shouldn't be done after the swsusp's memory
> +shrinker has run.  Also, there may be some operations, that subsystems may want
> +to carry out before a suspend or after a resume, requiring the system to be
> +fully functional, so the drivers' .suspend() and .resume() routines are not
> +suitable for this purpose.
> +
> +The subsystems that have such needs can register suspend notifiers that will be
> +notified of the following events by the suspend core:
> +
> +SUSPEND_PREPARE		the system is going to suspend, tasks will be frozen
> +			immediately
> +
> +SUSPEND_ENTER_PREPARE	tasks have been frozen, memory is going to be freed
> +			and devices are going to be suspended
> +
> +SUSPEND_THAW_PREPARE	devices have been resumed, tasks will be thawed
> +			immediately
> +
> +SUSPEND_FINISHED	the resume is complete, the system is fully functional

+ This hook is called even if suspend fails, so that we do not
+ leak memory.


?

Looks ok to me.

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html