Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758343Ab1BRTW7 (ORCPT ); Fri, 18 Feb 2011 14:22:59 -0500 Received: from kroah.org ([198.145.64.141]:35144 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754922Ab1BRTWz (ORCPT ); Fri, 18 Feb 2011 14:22:55 -0500 Date: Fri, 18 Feb 2011 11:22:41 -0800 From: Greg KH To: "R. J. Wysocki" Cc: Alan Stern , Linux-pm mailing list , Kevin Hilman , Grant Likely , LKML , Magnus Damm , Len Brown , Mark Brown Subject: Re: [PATCH] PM: Make system-wide PM and runtime PM treat subsystems consistently Message-ID: <20110218192241.GA6172@kroah.com> References: <201102170045.48975.rjw@sisk.pl> <20110217170441.GA31809@kroah.com> <201102180054.25603.rwys@fuw.edu.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201102180054.25603.rwys@fuw.edu.pl> 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 Content-Length: 2874 Lines: 58 On Fri, Feb 18, 2011 at 12:54:25AM +0100, R. J. Wysocki wrote: > From: Rafael J. Wysocki > > The code handling system-wide power transitions (eg. suspend-to-RAM) > can in theory execute callbacks provided by the device's bus type, > device type and class in each phase of the power transition. In > turn, the runtime PM core code only calls one of those callbacks at > a time, preferring bus type callbacks to device type or class > callbacks and device type callbacks to class callbacks. > > It seems reasonable to make them both behave in the same way in that > respect. Moreover, even though a device may belong to two subsystems > (eg. bus type and device class) simultaneously, in practice power > management callbacks for system-wide power transitions are always > provided by only one of them (ie. if the bus type callbacks are > defined, the device class ones are not and vice versa). Thus it is > possible to modify the code handling system-wide power transitions > so that it follows the core runtime PM code (ie. treats the > subsystem callbacks as mutually exclusive). > > On the other hand, the core runtime PM code will choose to execute, > for example, a runtime suspend callback provided by the device type > even if the bus type's struct dev_pm_ops object exists, but the > runtime_suspend pointer in it happens to be NULL. This is confusing, > because it may lead to the execution of callbacks from different > subsystems during different operations (eg. the bus type suspend > callback may be executed during runtime suspend of the device, while > the device type callback will be executed during system suspend). > > Make all of the power management code treat subsystem callbacks in > a consistent way, such that: > (1) If the device's type is defined (eg. dev->type is not NULL) > and its pm pointer is not NULL, the callbacks from dev->type->pm > will be used. > (2) If dev->type is NULL or dev->type->pm is NULL, but the device's > class is defined (eg. dev->class is not NULL) and its pm pointer > is not NULL, the callbacks from dev->class->pm will be used. > (3) If dev->type is NULL or dev->type->pm is NULL and dev->class is > NULL or dev->class->pm is NULL, the callbacks from dev->bus->pm > will be used provided that both dev->bus and dev->bus->pm are > not NULL. > > Signed-off-by: Rafael J. Wysocki > Acked-by: Kevin Hilman > Reasoning-sounds-sane-to: Grant Likely Acked-by: Greg Kroah-Hartman You are going to take this through your tree, right? thanks, greg k-h -- 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/