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Date: Thu, 6 May 2010 11:36:05 -0700
From: Tony Lindgren <tony@atomide.com>
To: Daniel Walker <dwalker@fifo99.com>
Cc: Matthew Garrett <mjg@redhat.com>, Brian Swetland <swetland@google.com>,
       Alan Stern <stern@rowland.harvard.edu>,
       mark gross <mgross@linux.intel.com>, markgross@thegnar.org,
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       Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [linux-pm] [PATCH 1/8] PM: Add suspend block api.
Message-ID: <20100506183605.GF30928@atomide.com>
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* Daniel Walker <dwalker@fifo99.com> [100506 10:30]:
> On Thu, 2010-05-06 at 10:14 -0700, Tony Lindgren wrote:
> > * Matthew Garrett <mjg@redhat.com> [100506 10:05]:
> > > On Thu, May 06, 2010 at 10:01:51AM -0700, Tony Lindgren wrote:
> > > 
> > > > Or are you suspending constantly, tens of times per minute even if
> > > > there's no user activity?
> > > 
> > > In this case you'd be repeatedly trying to suspend until the modem 
> > > driver stopped blocking it. It's pretty much a waste.
> > 
> > But then the userspace knows you're getting data from the modem, and
> > it can kick some inactivity timer that determines when to try to
> > suspend next.
> 
> If the idle thread was doing the suspending then the inactivity timer by
> it's self could block suspend. As long as the idle thread was setup to
> check for timers. I'm sure that _isn't_ the point your trying to make.
> It just makes gobs more sense to me that the idle thread does the
> suspending .. Your idle, so depending on how long your idle then you
> suspend.

The alternative logic I'm suggesting is get the GUI into idle mode as
soon as possible, then limp along with off-while-idle or
retention-while-idle until some timer expires, then suspend the whole
device.

Tony