From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756180AbZBWXxu (ORCPT ); Mon, 23 Feb 2009 18:53:50 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751984AbZBWXxm (ORCPT ); Mon, 23 Feb 2009 18:53:42 -0500 Received: from ogre.sisk.pl ([217.79.144.158]:42363 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751572AbZBWXxl convert rfc822-to-8bit (ORCPT ); Mon, 23 Feb 2009 18:53:41 -0500 From: "Rafael J. Wysocki" To: Arve =?iso-8859-1?q?Hj=F8nnev=E5g?= Subject: Re: [RFD] Automatic suspend Date: Tue, 24 Feb 2009 00:53:08 +0100 User-Agent: KMail/1.11.0 (Linux/2.6.29-rc5-tst; KDE/4.2.0; x86_64; ; ) Cc: Alan Stern , "Woodruff, Richard" , Arjan van de Ven , Kyle Moffett , Oliver Neukum , Benjamin Herrenschmidt , pm list , LKML , Pavel Machek , Nigel Cunningham , Matthew Garrett , mark gross , Uli Luckas , Igor Stoppa , Brian Swetland , Len Brown References: <200902192215.18365.rjw@sisk.pl> <200902212120.37684.rjw@sisk.pl> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8BIT Content-Disposition: inline Message-Id: <200902240053.11164.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday 24 February 2009, Arve Hjønnevåg wrote: > On Sat, Feb 21, 2009 at 12:20 PM, Rafael J. Wysocki wrote: > > On Saturday 21 February 2009, Arve Hjønnevåg wrote: > >> On Sat, Feb 21, 2009 at 1:47 AM, Rafael J. Wysocki wrote: > >> > On Saturday 21 February 2009, Arve Hjønnevåg wrote: > >> >> On Fri, Feb 20, 2009 at 3:57 PM, Rafael J. Wysocki wrote: > >> >> > On Saturday 21 February 2009, Arve Hjønnevåg wrote: > >> >> >> On Fri, Feb 20, 2009 at 7:56 AM, Rafael J. Wysocki wrote: > >> >> >> > On Friday 20 February 2009, Arve Hjønnevåg wrote: > >> >> >> >> On Fri, Feb 20, 2009 at 2:49 AM, Rafael J. Wysocki wrote: > >> >> >> >> > On Friday 20 February 2009, Arve Hjønnevåg wrote: > >> >> >> >> >> On Thu, Feb 19, 2009 at 2:08 PM, Alan Stern wrote: > > [--snip--] > >> >> > The idea is to have both /sys/power/state and /sys/power/sleep at the same > >> >> > time, where /sys/power/state will work just like it does right now. Sure, > >> >> > there must be mutual exclusion between the two, but that's a matter of > >> >> > implementation IMO. > >> >> > >> >> If you want to only prevent suspend though one interface, you have to > >> >> also pass information to the driver about its suspend hook is being > >> >> called so it can conditionally return -EBUSY. The wakelock interface > >> >> requires less code in each driver. > >> > > >> > Well, I don't think so. Moreover, it requires you to spread wakelocks all > >> > over the place if you don't use the timeouted ones which, let's face it, is > >> > hardly acceptable. > >> > >> Your method does not reduce the number of places that has to be > >> modified. Any component where we add a wakelock, you have to add a > >> suspend handler to abort suspend when we would have held a wakelock. > > > > Well, maybe not, but it doesn't introduce entirely new API for device drivers. > > Instead, it extends the existing interfaces which I think is more appropriate. > > The existing interfaces require polling. I don't think extending these > interfaces to make the polling faster is a better solution than adding > an interface to avoid polling. > > Also, with your solution, how would you modify evdev.c to prevent > suspend while the event queue is not empty. This code does not have > any suspend hooks and the queue is not tied to any thread. Well, why do you need to modify evdev.c in the first place? Rafael