Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759466Ab0HFASY (ORCPT ); Thu, 5 Aug 2010 20:18:24 -0400 Received: from mail.lang.hm ([64.81.33.126]:56679 "EHLO bifrost.lang.hm" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751662Ab0HFASW (ORCPT ); Thu, 5 Aug 2010 20:18:22 -0400 Date: Thu, 5 Aug 2010 17:16:44 -0700 (PDT) From: david@lang.hm X-X-Sender: dlang@asgard.lang.hm To: Brian Swetland cc: paulmck@linux.vnet.ibm.com, kevin granade , =?ISO-8859-15?Q?Arve_Hj=F8nnev=E5g?= , Matthew Garrett , "Rafael J. Wysocki" , Arjan van de Ven , linux-pm@lists.linux-foundation.org, linux-kernel@vger.kernel.org, pavel@ucw.cz, florian@mickler.org, stern@rowland.harvard.edu, peterz@infradead.org, tglx@linutronix.de, alan@lxorguk.ukuu.org.uk Subject: Re: Attempted summary of suspend-blockers LKML thread In-Reply-To: Message-ID: References: <20100805004802.GP24163@linux.vnet.ibm.com> <20100805151211.GA10080@linux.vnet.ibm.com> <20100805203102.GN2447@linux.vnet.ibm.com> <20100805230304.GQ2447@linux.vnet.ibm.com> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1665 Lines: 38 On Thu, 5 Aug 2010, Brian Swetland wrote: > On Thu, Aug 5, 2010 at 4:03 PM, Paul E. McKenney > wrote: >>>> so what would wake a phone up from suspend where the phone should go back to >>>> sleep in under a second? >>> >>> Here are some real-world examples from shipped android devices: >>> - battery gauging happens every 10 minutes, need to wake long enough >>> to chatter with the 1w interface and make sure the battery is not >>> exploding >>> - always on mail/im/calendar/etc sync often has network events that >>> happen every 5-10 minutes which cause devices to briefly wake up and >>> return to sleep >>> - gps tracker app might wake every couple minutes or every n gps >>> events to log location >>> - low power audio subsystems can wake you up every 1-4 seconds (pcm) >>> or 1-4 minutes (mp3) to fetch more data >> >> Interesting! >> >> So for an mp3 playback, does an Android suspend between data fetches? > > It can if the latency is long enough (which is why I point out low > power audio which is usually high latency). For low latency (system > sounds, etc) 10-25ms between buffers it's not practical to fully > suspend but we will go to the lowest power state in idle if possible. the playback is able to continue even with all the clocks stopped? that surprises me. I would hav expected it to be able to sleep while playing audio, but not do a full suspend. David Lang -- 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/