From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758458Ab1DZVME (ORCPT ); Tue, 26 Apr 2011 17:12:04 -0400 Received: from ksp.mff.cuni.cz ([195.113.26.206]:47387 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1758342Ab1DZVMC (ORCPT ); Tue, 26 Apr 2011 17:12:02 -0400 Date: Tue, 26 Apr 2011 23:11:59 +0200 From: Pavel Machek To: "Rafael J. Wysocki" Cc: Greg KH , MyungJoo Ham , linux-pm@lists.linux-foundation.org, Len Brown , "Jean Delvare (PC drivers core)" , "Ben Dooks (embedded platforms)" , kyungmin.park@samsung.com, myungjoo.ham@gmail.com, LKML , Alan Stern Subject: Re: [RFC PATCH v2 1/3] PM / Core: suspend_again callback for device PM. Message-ID: <20110426211159.GB28033@elf.ucw.cz> References: <1303288106-2965-1-git-send-email-myungjoo.ham@samsung.com> <20110426131737.GA13597@suse.de> <20110426203853.GC27140@elf.ucw.cz> <201104262249.22564.rjw@sisk.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201104262249.22564.rjw@sisk.pl> X-Warning: Reading this can be dangerous to your mental health. 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 Hi! > > > What is the root problem that this is trying to solve? > > > > It is trying to fix machines that need to run periodic kernel tasks > > even when user asked them to sleep. Zaurus needs to periodicaly wake > > up to be able to charge battery in s2ram state, for example. > > Well, if you wake up periodically, it's not S2RAM any more, I'd say. It certainly looks a lot like s2ram to the user. Now, your PC wakes up periodically in s2ram, too; but it is keyboard controller that wakes up, not CPU, so you do not know. On Zaurus, you do not know, either; nothing visible happens and userspace is shielded from these details. Should user really have to know if battery charger is implemented on keyboard controller or on main cpu before he selects which interface to use? Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html