Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754273Ab0FFIcS (ORCPT ); Sun, 6 Jun 2010 04:32:18 -0400 Received: from mail-gw0-f46.google.com ([74.125.83.46]:47927 "EHLO mail-gw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753300Ab0FFIcO convert rfc822-to-8bit (ORCPT ); Sun, 6 Jun 2010 04:32:14 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=k20SXmd0SUB351RqFGyg7a6/faseGHWHny9Ke9IEdDPCOjYnan7hxnL+XStUuQvKyY XStxzaT8wAnCla3EyoFwonqdztoNUb9HIjkI/FJ85wl6ed/Girg0Ut91MQPIkoJ+em8M ICiN60GTt8hopK2JxS3wb7EJEtxud8LGylXvg= MIME-Version: 1.0 In-Reply-To: References: <20100603193045.GA7188@elte.hu> <20100603231153.GA11302@elte.hu> <20100603232302.GA16184@elte.hu> <20100604071354.GA14451@elte.hu> <20100604083423.GD15181@elte.hu> <1275653210.27810.39762.camel@twins> <1275731653.27810.41078.camel@twins> <20100605092851.6ee15f13@infradead.org> Date: Sun, 6 Jun 2010 10:32:13 +0200 Message-ID: Subject: Re: [linux-pm] suspend blockers & Android integration From: Vitaly Wool To: Brian Swetland Cc: =?ISO-8859-1?Q?Arve_Hj=F8nnev=E5g?= , Arjan van de Ven , tytso@mit.edu, Florian Mickler , Peter Zijlstra , "H. Peter Anvin" , LKML , Neil Brown , James Bottomley , Alan Cox , Linux PM , Ingo Molnar , Linux OMAP Mailing List , Linus Torvalds , Thomas Gleixner , Felipe Balbi 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 Content-Length: 2379 Lines: 49 On Sun, Jun 6, 2010 at 10:20 AM, Brian Swetland wrote: > On Sun, Jun 6, 2010 at 12:52 AM, Vitaly Wool wrote: >> 2010/6/5 Arve Hj?nnev?g : >>> >>> We clearly have different standards for what we consider good. We >>> measure time suspended in minutes or hours, not seconds, and waking up >>> every second or two causes a noticeable decrease in battery life on >>> the hardware we have today. >> >> Are you stating that the existing Android implementation enters the >> suspended state for hours for any of the existing designs? > > It varies depending on device and usage. ?The battery monitoring on > NexusOne happens every ten minutes, so that's the longest you'll see a > N1 suspended for. ?On a G1 or Dream/myTouch you can see 20-30 minutes > between wakeups (depending on network issues and background data sync > traffic), and if you have background data sync off those devices can > sit in suspend for days at a time (unless you receive a phone call or > something). ?In "airplane mode", with no local alarms, a device can > easily sit in the lowest power state for a month or so, until the > battery finally runs out. That only concerns the case when you have just turned on the phone and left it laying around. You have to admit that it's not the common case for a smartphone. The common case is that you've played with it for a bit, turning on things like BT/WIFI, running some apps and so on. And doing so you'll end up having wake locks taken from everywhere, so I can hardly see a second of suspend for Nexus. E. g. when the wireless is connected to an AP, it takes a wake lock which is released on 15 minutes touchscreen inactivity timeout, as far as I can tell. So: * the system will never hit suspend during this period; * if the download was ongoing and had not been completed during this period, it will be terminated. So the bottom line is: the approach is very inflexible. Of course it can give you the best power savings if you turn the Airplane mode on as soon as you switched on the phone, but this is not what a typical user would do. ~Vitaly -- 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/