From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756737Ab0EEUDM (ORCPT ); Wed, 5 May 2010 16:03:12 -0400 Received: from cavan.codon.org.uk ([93.93.128.6]:57694 "EHLO cavan.codon.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752062Ab0EEUDK (ORCPT ); Wed, 5 May 2010 16:03:10 -0400 Date: Wed, 5 May 2010 21:02:43 +0100 From: Matthew Garrett To: Mark Brown Cc: Alan Stern , Brian Swetland , "Rafael J. Wysocki" , Kevin Hilman , Arve Hj?nnev?g , linux-pm@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Tejun Heo , Oleg Nesterov , Paul Walmsley , magnus.damm@gmail.com, mark gross , Arjan van de Ven , Geoff Smith , rebecca@android.com Subject: Re: [PATCH 0/8] Suspend block api (version 6) Message-ID: <20100505200243.GA6266@srcf.ucam.org> References: <20100505185225.GA4411@srcf.ucam.org> <20100505192208.GB5085@srcf.ucam.org> <20100505195249.GC11441@sirena.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100505195249.GC11441@sirena.org.uk> User-Agent: Mutt/1.5.18 (2008-05-17) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: mjg59@cavan.codon.org.uk X-SA-Exim-Scanned: No (on cavan.codon.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 05, 2010 at 08:52:50PM +0100, Mark Brown wrote: > On Wed, May 05, 2010 at 08:22:08PM +0100, Matthew Garrett wrote: > > Perhaps you could infer that from the audio routing setup? I don't know > > enough about embedded codecs. > > Yes, you can providing we extract a bit more information from the > machine drivers and/or userspace - we already do our power management > based on paths. The implementation I'd do here is to provide a facility > for marking some of the path endpoints as suspend insensitive then on > suspend leave those endpoints in their current state, force the other > endpoints off temporarily and re-run the standard power checks. One thing that's been mentioned before is that some vendors can swap the kernel much more easily than they can swap userspace, with the added constraint that they have little control over the bootloader. So if there's a userspace interface, it may well also be helpful to provide a kernel hook to allow the platform setup code to configure things. But otherwise, I think that'd work for audio - the only question is whether we need it to be more generic. -- Matthew Garrett | mjg59@srcf.ucam.org