From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756306Ab1AaW3Q (ORCPT ); Mon, 31 Jan 2011 17:29:16 -0500 Received: from mail-gw0-f46.google.com ([74.125.83.46]:51662 "EHLO mail-gw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753857Ab1AaW3P (ORCPT ); Mon, 31 Jan 2011 17:29:15 -0500 Date: Mon, 31 Jan 2011 15:26:09 -0700 From: Grant Likely To: "Rafael J. Wysocki" Cc: Alan Stern , Magnus Damm , Linux-pm mailing list , Greg KH , LKML , Kevin Hilman , Len Brown Subject: Re: [RFC][PATCH] Power domains for platform bus type Message-ID: <20110131222609.GC27856@angua.secretlab.ca> References: <201101312316.52116.rjw@sisk.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201101312316.52116.rjw@sisk.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 On Mon, Jan 31, 2011 at 11:16:51PM +0100, Rafael J. Wysocki wrote: > On Monday, January 31, 2011, Alan Stern wrote: > > On Mon, 31 Jan 2011, Rafael J. Wysocki wrote: > > > > > On Monday, January 31, 2011, Alan Stern wrote: > > > > On Sun, 30 Jan 2011, Rafael J. Wysocki wrote: > > > > > > > > > > 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? > > > > > > > > Yes. But what about the platform_bus_set_pm_ops() interface? Should > > > > platform-specific replacements for the pm_ops functions also include > > > > the power_domain callbacks? > > > > > > Well, whoever uses platform_bus_set_pm_ops(), he can simply prevent power > > > domains from being used by not defining them in the first place. :-) > > > > But what about the case where the user _does_ want to have power > > domains? > > Ah, OK. The caller of platform_bus_set_pm_ops() will replace the original > platform_dev_pm_ops with his own set of operations, so he will not see the > power domains. > > > Do you want to make the replacement routines responsible for > > invoking the power-domain callbacks, or should the platform core handle > > this automatically? > > Well, if someone replaces the entire platform_dev_pm_ops object, this means > that on his platform power management is substantially different from the > generic one. In that case, IMO, he should be responsible for handling all > of the subsystem-level aspects of power management, including power domains. Part of point of doing something like power_domain is to *get rid* of platform_bus_set_pm_ops(). It is a horrid, stop-gap interface that doesn't scale. I don't think much consideration needs to be made for users of platform_bus_set_pm_ops() in this regard. g.