From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762734AbXGKK53 (ORCPT ); Wed, 11 Jul 2007 06:57:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759746AbXGKK5V (ORCPT ); Wed, 11 Jul 2007 06:57:21 -0400 Received: from ogre.sisk.pl ([217.79.144.158]:49224 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758842AbXGKK5U convert rfc822-to-8bit (ORCPT ); Wed, 11 Jul 2007 06:57:20 -0400 From: "Rafael J. Wysocki" To: Miklos Szeredi Subject: Re: Hibernation Redesign Date: Wed, 11 Jul 2007 13:04:39 +0200 User-Agent: KMail/1.9.5 Cc: a1426z@gawab.com, jeremy@goop.org, jbms@cmu.edu, pavel@ucw.cz, nickpiggin@yahoo.com.au, linux-kernel@vger.kernel.org, akpm@linux-foundation.org References: <200707081737.21932.a1426z@gawab.com> <200707111227.52609.rjw@sisk.pl> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Content-Disposition: inline Message-Id: <200707111304.40504.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday, 11 July 2007 12:42, Miklos Szeredi wrote: > > > > Yes, I suppose. You're certain the old kernel's devices are completely > > > > quiescent at that point? > > > > > > That's exactly the problem; trying to save a state from within the > > > kernel would probably necessitate a freezer hack, which we are > > > trying so dearly to avoid. > > > > Well, I don't think that avoiding the freezer whatever it takes > > would be a good idea. There needs to be some balance. ;-) > > Well, it takes some extra locking in the drivers. Which is needed > _anyway_ if we want to have a working s2ram without the freezer. > > With the kexec approach, I don't see any extra requirements from the > kernel to be able to drop the freezer. This is not my point. I think that if what it takes to implement the kexec approach, as a complete working solution, is much more complicated than what we have now, then the current soultion is favorable. Anyway, to implement the kexec approach we must separate the hibernation from the suspend at the drivers level, which I'm still going to do, but I need to take part in endless discussions regarding the freezer, how it is bad and how we should drop it, because it breaks things (which NB is not true, because it doesn't). >>From a practical point of view, the freezer is not the most problematic part of the infrastructure. For example, none of the bug reports that we have registered in the bugzilla is related to the freezer. Moreover, to drop it, we first need to redesign the other things. Greetings, Rafael -- "Premature optimization is the root of all evil." - Donald Knuth