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Date: Mon, 21 Jun 2010 17:57:49 +0200
From: Pavel Machek <pavel@ucw.cz>
To: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Thomas Gleixner <tglx@linutronix.de>, Alan Cox <alan@lxorguk.ukuu.org.uk>,
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Subject: Re: [linux-pm] [PATCH 0/8] Suspend block api (version 8)
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Hi!

(ok, so I'm little late to the party).

> > Nonsense, if we want to push the system into suspend from the idle
> > state we can do that. It's just not implemented and we've never tried
> > to do it as it requires a non trivial amount of work, but I have done
> > it on an ARM two years ago as a prove of concept and it works like a
> > charm.
> 
> ACPI provides no guarantees about what level of hardware functionality 
> remains during S3. You don't have any useful ability to determine which 
> events will generate wakeups. And from a purely practical point of view, 

We'll need ACPI extensions, then (or very conservative
drivers). suspend blockers do *not* help here.

> since the latency is in the range of seconds, you'll never have a low 
> enough wakeup rate to hit it.

I did 'sleepy linux' prototype on PC, and yes I was able to get to
'once in 5 seconds' wakeup rate... good enough...
									Pavel

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