Re: ACPI code in platform mode hibernation code paths (was: Re: [PATCH] swsusp: do not use pm_ops)

[Pavel Machek <pavel@ucw.cz>]

Hi!

Crazy idea... could we kill hibernate_ops-like struct, and just create
a device for ACPI, using its suspend()/resume()/whatever callbacks to
do the ACPI magic?

> Okay.  Since we're trying to separate the hibernation code from the
> suspend code anyway, we can use the opportunity to introduce some new
> callbacks for the hibernation and/or redefine the existing ones.
> 
> The spec suggests that we need the following callbacks:
> 
> (1) prepare() - called after device_suspend(), execute _PTS and
> disable GPEs

sysdev .suspend() method would do the trick.

> (2) cancel() - called at any time after prepare() if there's an error, execute
>     _WAK and enable run-time GPEs

sysdev .resume() should do the trick. 

> (3) enter() - called after the image has been saved, execute _GTS and do what's
>     currently done in pm_enter()

This one is tricky. It is essentially
powerdown_but_enter_S4_instead. I guess we can live with if()... as we
need to special-case reboot in the same place.

> (4) finish() - called after the image has been restored, do what's currently
>     done in pm_finish()

platform (?) device .resume() method should work.
									Pavel
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