From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758026Ab1DZUi5 (ORCPT ); Tue, 26 Apr 2011 16:38:57 -0400 Received: from ksp.mff.cuni.cz ([195.113.26.206]:43791 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754901Ab1DZUi4 (ORCPT ); Tue, 26 Apr 2011 16:38:56 -0400 Date: Tue, 26 Apr 2011 22:38:53 +0200 From: Pavel Machek To: Greg KH Cc: "Rafael J. Wysocki" , 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: <20110426203853.GC27140@elf.ucw.cz> References: <1303288106-2965-1-git-send-email-myungjoo.ham@samsung.com> <1303781471-2477-1-git-send-email-myungjoo.ham@samsung.com> <201104261347.21811.rjw@sisk.pl> <20110426131737.GA13597@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110426131737.GA13597@suse.de> 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! > > To conclude, I'm not sure about the approach. In particular, I'm not sure > > if the benefit is worth the effort and the resulting complications (ie. the > > possibility of having to deal with wakeup signals not requested by user > > space) seem to be a bit too far reaching. > > > > Greg, what do you think? > > I agree with you in that I don't think that this type of feature is > valid at the moment. Our current "solution" is low level suspend code on Zaurus directly looking at charger state and doing the "wakeup or not" decision by hand. > I don't understand why our current situation doesn't work, what are we > lacking that is needed for these systems that we have not seen > before? It works, but it is ugly; and it seems samsung now needs similar hacks. > 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. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html