Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754692AbZFHNW4 (ORCPT ); Mon, 8 Jun 2009 09:22:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753648AbZFHNWs (ORCPT ); Mon, 8 Jun 2009 09:22:48 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:44430 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753267AbZFHNWr (ORCPT ); Mon, 8 Jun 2009 09:22:47 -0400 Date: Mon, 8 Jun 2009 15:22:35 +0200 From: Ingo Molnar To: Matthew Garrett Cc: "Rafael J. Wysocki" , Alan Stern , pm list , ACPI Devel Maling List , LKML , Magnus Damm Subject: Re: Run-time PM idea (was: Re: [linux-pm] [RFC][PATCH 0/2] PM: Rearrange core suspend code) Message-ID: <20090608132235.GC13214@elte.hu> References: <200906072347.00580.rjw@sisk.pl> <20090608065419.GA13568@elte.hu> <200906081330.50045.rjw@sisk.pl> <20090608130509.GA3272@elte.hu> <20090608131159.GA15100@srcf.ucam.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090608131159.GA15100@srcf.ucam.org> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1572 Lines: 36 * Matthew Garrett wrote: > On Mon, Jun 08, 2009 at 03:05:09PM +0200, Ingo Molnar wrote: > > > > * Rafael J. Wysocki wrote: > > > Well, we've been discussing it for quite a while and since more > > > and more people are interested, I'm giving it a high priority. > > > > Cool. I think that if within a few years we could achieve that every > > default distro (both on desktops and on servers) triggers PM > > functionality runtime on common hardware, we'd both have lower power > > consumption in general, and we'd have more robust suspend-resume > > code as well. > > The difficulty is in determining when it's viable to autosuspend a > given device. There's a limit to how much we can determine purely > from kernel state (for instance, we could suspend ahci when > there's no pending disk access, but we'd lose hotplug > notifications) so there's going to have to be some level of > userspace policy determination. Having the infrastructure in the > kernel is an important part of this, but there'll be some distance > to go after that. What will the 'user space policy' bit do what the kernel cannot? If you mean the user has to configure something manually - that wont really happen in practice. We are happy if they know where to put those USB sticks in ;-) Ingo -- 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/