Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756012AbYCZOKW (ORCPT ); Wed, 26 Mar 2008 10:10:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754767AbYCZOKE (ORCPT ); Wed, 26 Mar 2008 10:10:04 -0400 Received: from iolanthe.rowland.org ([192.131.102.54]:44920 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1754764AbYCZOKB (ORCPT ); Wed, 26 Mar 2008 10:10:01 -0400 Date: Wed, 26 Mar 2008 10:10:01 -0400 (EDT) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: "Rafael J. Wysocki" cc: Oliver Neukum , ACPI Devel Maling List , , Alexey Starikovskiy , Johannes Berg , LKML Subject: Re: [linux-pm] [RFC][PATCH] PM: Introduce new top level =?iso-8859-1?q?suspend=09and_hibernation_callbacks?= (rev. 2) In-Reply-To: <200803252156.12185.rjw@sisk.pl> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2160 Lines: 50 On Tue, 25 Mar 2008, Rafael J. Wysocki wrote: > On Tuesday, 25 of March 2008, Oliver Neukum wrote: > > Am Dienstag, 25. M?rz 2008 21:41:48 schrieb Rafael J. Wysocki: > > > On Tuesday, 25 of March 2008, Oliver Neukum wrote: > > > > Am Dienstag, 25. M?rz 2008 15:33:22 schrieb Alan Stern: > > > > > > so I'd say a > > > > > > failure to resume is just a limited subcase of a device vanishing during > > > > > > sleep. > > > > > > > > > > I'll go along with that. ?If a device vanishes during sleep, the PM > > > > > core isn't responsible for unregistering it -- the device's subsystem > > > > > is. > > > > > > > > Yes, that makes sense. You are right. > > > > > > Still, if ->resume() returns an error, does it make sense, from the PM core's > > > point of view, to execute ->complete() for that device, for example? > > > > IMO you must always keep the ordering invariant. If a parent returns an error > > the PM core must not wake its children. Don't think of it that way. The PM core doesn't wake anything. It merely notifies drivers that the system sleep is ending, so that the drivers can wake their devices. It's up to the driver to detect whether the parent failed to resume, in which case the driver should take appropriate action. The situation is no different from what happens when the user tries to access a mounted USB disk drive after the USB cable has been unplugged. The drivers take care of everything. > I'm agreeing here, but one of the previous Alan's comments suggests he has a > differing opinion. Alan? > > I'm considering to make the PM core skip the resuming of the children of > devices that failed to resume and skip calling ->complete() for that devices > and their children. While that might in principle be a reasonable thing to do, it's different from how the PM core has behaved in the past. I don't see any point in making a change like that now. Alan Stern -- 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/