From mboxrd@z Thu Jan  1 00:00:00 1970
From: Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [linux-pm] [PATCH 0/8] Suspend block api (version 8)
Date: Thu, 27 May 2010 20:14:30 +0200 (CEST)
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To: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Peter Zijlstra <peterz@infradead.org>, Alan Stern <stern@rowland.harvard.edu>, Paul@smtp1.linux-foundation.org, LKML <linux-kernel@vger.kernel.org>, Florian Mickler <florian@mickler.org>, felipe.balbi@nokia.com, Linux OMAP Mailing List <linux-omap@vger.kernel.org>, Linux PM <linux-pm@lists.linux-foundation.org>, Alan Cox <alan@lxorguk.ukuu.org.uk>
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On Thu, 27 May 2010, Matthew Garrett wrote:

> On Thu, May 27, 2010 at 07:34:40PM +0200, Peter Zijlstra wrote:
> > > we still need to be able to enter suspend while the system isn't idle.
> > 
> > _WHY_!?
> 
> Because if I'm running a kernel build in a tmpfs and I hit the sleep 
> key, I need to go to sleep. Blocking processes on driver access isn't 
> sufficient.

That's the difference between opportunistic and enforced suspend. On
enforced suspend the QoS guarantee is forced to NONE for everything
and you go down no matter what. When you decide to push the wakeup
button the system restores.

Thanks,

	tglx