From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754924Ab1A3Wjz (ORCPT ); Sun, 30 Jan 2011 17:39:55 -0500 Received: from ogre.sisk.pl ([217.79.144.158]:50650 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752721Ab1A3Wjy (ORCPT ); Sun, 30 Jan 2011 17:39:54 -0500 From: "Rafael J. Wysocki" To: Alan Stern Subject: Re: [RFC][PATCH] Power domains for platform bus type Date: Sun, 30 Jan 2011 23:39:02 +0100 User-Agent: KMail/1.13.5 (Linux/2.6.38-rc2+; KDE/4.4.4; x86_64; ; ) Cc: "Linux-pm mailing list" , Greg KH , LKML , Magnus Damm , Kevin Hilman , Grant Likely , Len Brown References: In-Reply-To: MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201101302339.02993.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sunday, January 30, 2011, Alan Stern wrote: > On Sun, 30 Jan 2011, Rafael J. Wysocki wrote: > > > Hi, > > > > This is something we discussed during the last Linux Plumbers Conference. > > > > The problem appears to be that the same device may be used in different > > systems in different configurations such that actions necessary for the > > device's power management can vary from one system to another. In those > > cases the drivers' power management callbacks are generally not sufficient, > > because they can't take the configuration of the whole system into account. > > > > I think this issue may be addressed by adding objects that will represent > > power domains and will provide power management callbacks to be executed > > in addition to the device driver's PM callbacks, which is done by the patch > > below. > > > > Please have a look at it and tell me what you think. > > One thing about this implementation is slightly questionable. The new > power_domain callbacks were added to the __weak platform PM routines, > which means they will have to be included in every overriding routine > provided by a platform imiplementation. > > Would it be better to separate these things? Have the power_domain > callbacks occur in a static outer function which then calls a public > __weak inner function that can be overridden? That certainly is a good idea, but I wasn't sure how to do that. It looks like I could keep the __weak functions as they are and modify platform_dev_pm_ops instead to point to a new set of function that in turn would call the __weak ones. For example, the .suspend pointer in platform_dev_pm_ops might point to a new function, say platform_pm_full_suspend() that would call the power domain functions and the "original" platform_pm_suspend(). Is that what you mean? Rafael