From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933212AbbIYTrS (ORCPT ); Fri, 25 Sep 2015 15:47:18 -0400 Received: from v094114.home.net.pl ([79.96.170.134]:54631 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S933178AbbIYTrP (ORCPT ); Fri, 25 Sep 2015 15:47:15 -0400 From: "Rafael J. Wysocki" To: Alan Stern Cc: Oliver Neukum , Dmitry Torokhov , Irina Tirdea , Len Brown , Octavian Purdila , "Rafael J. Wysocki" , Ulf Hansson , Pavel Machek , "linux-input@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-pm@vger.kernel.org" Subject: Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing runtime suspend Date: Fri, 25 Sep 2015 22:15:28 +0200 Message-ID: <1825872.1pMPkfpiYH@vostro.rjw.lan> User-Agent: KMail/4.11.5 (Linux/4.1.0-rc5+; KDE/4.11.5; x86_64; ; ) In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday, September 25, 2015 10:29:55 AM Alan Stern wrote: > On Fri, 25 Sep 2015, Rafael J. Wysocki wrote: > > > We are missing the "no remote wakeup" bit now (well, there is a PM QoS flag, > > but it isn't very useful, so I'd prefer to replace it with a "no remote wakeup" > > bit in struct dev_pm_info or something similar). > > > > That is actually quite important, because (a) we can save energy but not > > configuring the device to do remote wakeup in the first place and (b) that > > may involve more than just the driver (for example, disabling PCI or ACPI > > remote wakeup involves the bus type or similar). > > > > So it looks like we need to be able to distinguish between "runtime suspend > > with remote wakeup" and "runtime suspend without remote wakeup". > > > > And if we do the latter, we may not even need the "inhibit" thing any more, > > because suspended devices without that are not configured to do remote wakeup > > cannot really signal anything in the majority of cases. > > That works only for drivers that use autosuspend to go to low power in > between events. It doesn't work for drivers that remain at full power > as long as the device file is open. That kind of driver does require > an "inhibit" interface. Or an interface allowing user space to trigger pm_request_idle() for them. So user space would change the "no remote wakeup" setting and then do the "try to suspend now" thing. Thanks, Rafael