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From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: Pavel Machek <pavel@suse.cz>
Subject: Re: [RFD] Automatic suspend
Date: Tue, 17 Feb 2009 00:00:41 +0100
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Cc: Arjan van de Ven <arjan@infradead.org>,
       pm list <linux-pm@lists.linux-foundation.org>,
       LKML <linux-kernel@vger.kernel.org>,
       "Arve Hj?nnev?g" <arve@android.com>,
       Alan Stern <stern@rowland.harvard.edu>,
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       Nigel Cunningham <nigel@nigel.suspend2.net>,
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       Igor Stoppa <igor.stoppa@nokia.com>,
       Brian Swetland <swetland@google.com>, Len Brown <lenb@kernel.org>
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On Monday 16 February 2009, Pavel Machek 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.

Well, I don't think it's viable to make any exceptions here.  Either we do it
or we don't.  And the agreement appears to be that we don't.

Thanks,
Rafael