Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758301Ab0HDG2M (ORCPT ); Wed, 4 Aug 2010 02:28:12 -0400 Received: from dspnet.fr ([188.165.44.67]:52514 "EHLO dspnet.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755611Ab0HDG2K (ORCPT ); Wed, 4 Aug 2010 02:28:10 -0400 Date: Wed, 4 Aug 2010 08:28:04 +0200 From: Olivier Galibert To: Arve =?iso-8859-1?B?SGr4bm5lduVn?= Cc: david@lang.hm, "Paul E. McKenney" , Arjan van de Ven , "Ted Ts'o" , linux-pm@lists.linux-foundation.org, linux-kernel , mjg59@srcf.ucam.org, pavel@ucw.cz, florian@mickler.org, rjw@sisk.pl, stern@rowland.harvard.edu, swetland@google.com, peterz@infradead.org, tglx@linutronix.de, alan@lxorguk.ukuu.org.uk Subject: Re: Attempted summary of suspend-blockers LKML thread Message-ID: <20100804062804.GA43413@dspnet.fr> References: <20100804001015.GJ2407@linux.vnet.ibm.com> <20100804045813.GA33951@dspnet.fr> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1997 Lines: 40 On Tue, Aug 03, 2010 at 11:03:15PM -0700, Arve Hj?nnev?g wrote: > 2010/8/3 Olivier Galibert : > > On Tue, Aug 03, 2010 at 08:39:22PM -0700, Arve Hj?nnev?g wrote: > >> If you just program the alarm you will wake up see that the monotonic > >> clock has not advanced and set the alarm another n seconds into the > >> future. Or are proposing that suspend should be changed to keep the > >> monotonic clock running? > > > > You're supposed to fix the clock after you wake up. ?That's part of > > the cost of going suspend. > > I'm not sure what you are referring to. The generic Linux timekeeping > code makes sure the monotonic clock stops while the system is > suspended regardless of what values the (hardware specific) > clocksource returns. That just means the android-like suspend should not act in that specific area the same as the generic suspend to ram. Which is not entirely surprising. In any case, it's not "keep the monotonic clock running", which would cost power. It's fix it up afterwards, using the same means you already do but perhaps at a higher level currently. People don't want to see the wrong time of the day just because the phone went to suspend. Laptop STR is different in perception because it shuts down things people don't want to see shutdown just by being idle, namely wifi connectivity. If your next polling timer is in half an hour and the screen/touchpad are off, you want to go as low in power as possible until then, and that's the deepest level of idle you can find that responds to alarms which may happen to be called suspend. But from a user point of view, it's just another idle level. And from a power management code/policy decisions point of view, it should be the same. OG. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/