From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753684AbZBTFfv (ORCPT ); Fri, 20 Feb 2009 00:35:51 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750794AbZBTFfm (ORCPT ); Fri, 20 Feb 2009 00:35:42 -0500 Received: from yx-out-2324.google.com ([74.125.44.30]:16017 "EHLO yx-out-2324.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750715AbZBTFfl convert rfc822-to-8bit (ORCPT ); Fri, 20 Feb 2009 00:35:41 -0500 MIME-Version: 1.0 In-Reply-To: <20090216232329.GA15678@srcf.ucam.org> References: <13B9B4C6EF24D648824FF11BE896716203771DD01B@dlee02.ent.ti.com> <20090216145948.6fea81c3@infradead.org> <200902170019.40599.rjw@sisk.pl> <20090216232329.GA15678@srcf.ucam.org> Date: Thu, 19 Feb 2009 21:35:39 -0800 Message-ID: Subject: Re: [RFD] Automatic suspend From: =?ISO-8859-1?Q?Arve_Hj=F8nnev=E5g?= To: Matthew Garrett Cc: "Rafael J. Wysocki" , Arjan van de Ven , "Woodruff, Richard" , Alan Stern , Kyle Moffett , Oliver Neukum , Benjamin Herrenschmidt , pm list , LKML , Pavel Machek , Nigel Cunningham , 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 16, 2009 at 3:23 PM, Matthew Garrett wrote: > On Tue, Feb 17, 2009 at 12:19:38AM +0100, Rafael J. Wysocki wrote: > >> This, again, seems to be a bit x86-centric. :-) The Android people are telling >> us that on the hardware they deal with it does make sense to put the entire >> system to sleep even for relatively short periods of time, since the latencies >> involved are not too bad. > > Arve said that the power state was equivalent in idle and suspend, but > that they preferred suspend because it stopped any periodic timers. I'd > be more interested in making sure that unnecessary timers aren't running > than focusing on automatically entering system-wide suspend - Nokia have > been managing this since 2005 with good results. I'm sure you can build a product with acceptable battery life without suspend. The average power draw on the G1 while idle with everything off is less than the power draw was in suspend on our previous hardware. However, on the same hardware you get 40 days standby using suspend versus 20 days using idle. If you turn on the radio and use the device every day, this starts to become irrelevant since you are lucky to get more than a few days standby time. However, if you install an application that wakes up 60 times a second (to check if it need to draw something on the screen) the difference between idle and suspend becomes 10 hours versus 40 days, or 10 hours versus 3 days with my use. -- Arve Hjønnevåg