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Date: Thu, 13 May 2010 21:34:12 +0100
From: Matthew Garrett <mjg@redhat.com>
To: Tony Lindgren <tony@atomide.com>
Cc: Alan Stern <stern@rowland.harvard.edu>, Paul Walmsley <paul@pwsan.com>,
       Arve =?iso-8859-1?B?SGr4bm5lduVn?= <arve@android.com>,
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Subject: Re: [linux-pm] [PATCH 0/8] Suspend block api (version 6)
Message-ID: <20100513203412.GA21244@srcf.ucam.org>
References: <alpine.DEB.2.00.1005122118530.7624@utopia.booyaka.com> <Pine.LNX.4.44L0.1005131002380.1695-100000@iolanthe.rowland.org> <20100513191717.GA3428@atomide.com> <20100513192522.GA19256@srcf.ucam.org> <20100513194205.GC3428@atomide.com> <20100513195349.GB19722@srcf.ucam.org> <20100513200003.GE3428@atomide.com> <20100513200814.GA20254@srcf.ucam.org> <20100513202320.GF3428@atomide.com>
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On Thu, May 13, 2010 at 01:23:20PM -0700, Tony Lindgren wrote:
> * Matthew Garrett <mjg@redhat.com> [100513 13:03]:
> > On Thu, May 13, 2010 at 01:00:04PM -0700, Tony Lindgren wrote:
> > 
> > > The system stays running because there's something to do. The system
> > > won't suspend until all the processors hit the kernel idle loop and
> > > the next_timer_interrupt_critical() returns nothing.
> > 
> > At which point an application in a busy loop cripples you.
> 
> Maybe you could deal with the misbehaving untrusted apps in the userspace
> by sending kill -STOP to them when the screen blanks? Then continue
> when some event wakes up the system again.

And if that's the application that's listening to the network socket 
that you want to get a wakeup event from? This problem is hard. I'd love 
there to be an elegant solution based on using the scheduler, but I 
really don't know what it is.

-- 
Matthew Garrett | mjg59@srcf.ucam.org