From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756289AbZBXACy (ORCPT ); Mon, 23 Feb 2009 19:02:54 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751910AbZBXACq (ORCPT ); Mon, 23 Feb 2009 19:02:46 -0500 Received: from el-out-1112.google.com ([209.85.162.179]:39642 "EHLO el-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751851AbZBXACp convert rfc822-to-8bit (ORCPT ); Mon, 23 Feb 2009 19:02:45 -0500 MIME-Version: 1.0 In-Reply-To: <200902240053.11164.rjw@sisk.pl> References: <200902192215.18365.rjw@sisk.pl> <200902212120.37684.rjw@sisk.pl> <200902240053.11164.rjw@sisk.pl> Date: Mon, 23 Feb 2009 16:02:42 -0800 Message-ID: Subject: Re: [RFD] Automatic suspend From: =?ISO-8859-1?Q?Arve_Hj=F8nnev=E5g?= To: "Rafael J. Wysocki" 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 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 23, 2009 at 3:53 PM, Rafael J. Wysocki wrote: > 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? It is the only code that knows that there are unprocessed input events. -- Arve Hjønnevåg