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Date: Mon, 16 Feb 2009 14:55:59 -0800
From: Arjan van de Ven <arjan@infradead.org>
To: Pavel Machek <pavel@suse.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>,
       pm list <linux-pm@lists.linux-foundation.org>,
       LKML <linux-kernel@vger.kernel.org>, Arve Hj?nnev?g <arve@android.com>,
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       Igor Stoppa <igor.stoppa@nokia.com>,
       Brian Swetland <swetland@google.com>, Len Brown <lenb@kernel.org>
Subject: Re: [RFD] Automatic suspend
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On Mon, 16 Feb 2009 23:51:16 +0100
Pavel Machek <pavel@suse.cz> wrote:

> Hi!
> 
> > > Userland should never ever control the state of a device like this
> > > directly. It should do so by a) closing the device and b) setting
> > > latency / functional requirements.
> > 
> > The user, however, may want to forcibly put a device into a low
> > power state without stopping all of the applications that depend on
> > it (eg. have it open). Do you think that we shouldn't allow users
> > to do such things?
> 
> I don't think we should do this... of you want device to be powered
> down, just don't keep it open. revoke should be enough :-).
> 
> ...one execption here is the disk driver; unmounting filesystems to
> let the disk spin down is probably too heavy.

but spin down happens on non-activity ;)
it's more a slumber than a power down



-- 
Arjan van de Ven 	Intel Open Source Technology Centre
For development, discussion and tips for power savings, 
visit http://www.lesswatts.org