Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933970AbbDQRai (ORCPT ); Fri, 17 Apr 2015 13:30:38 -0400 Received: from iolanthe.rowland.org ([192.131.102.54]:39861 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S933937AbbDQRag (ORCPT ); Fri, 17 Apr 2015 13:30:36 -0400 Date: Fri, 17 Apr 2015 13:30:35 -0400 (EDT) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: Laurent Pinchart cc: Tomeu Vizoso , , Dmitry Torokhov , "Rafael J. Wysocki" , Pavel Machek , Len Brown , Greg Kroah-Hartman , Subject: Re: [PATCH v3 1/2] PM / sleep: Let devices force direct_complete In-Reply-To: <1471135.f2mh84nZFq@avalon> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1570 Lines: 37 On Fri, 17 Apr 2015, Laurent Pinchart wrote: > Hi Tomeu, > > Thank you for the patch. > > On Friday 17 April 2015 17:24:49 Tomeu Vizoso wrote: > > Introduce a new per-device flag power.force_direct_complete that will > > instruct the PM core to ignore the runtime PM status of its descendants > > when deciding whether to let this device remain in runtime suspend when > > the system goes into a sleep power state. > > > > This is needed because otherwise it would be needed to get dozens of > > drivers to implement the prepare() callback and be runtime PM active > > even if they don't have a 1-to-1 relationship with a piece of HW. > > I'll let PM experts comment on the approach, but I believe the new flag would > benefit from being documented (likely in Documentation/power/devices.txt) :-) Documentation/power/runtime_pm.txt is the right place. However, I'm not sure that this is the sort of thing Rafael meant when he suggested adding a new flag. I thought he meant the PM core would look at the new flag only if there was no ->prepare method at all. Then if the new flag was set, the PM core would act as though ->prepare had returned 1. That way there would be no need to add silly little one-line *_prepare() routines all over the place. Maybe he had something else in mind, though... 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/