From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757001Ab0ECVjq (ORCPT ); Mon, 3 May 2010 17:39:46 -0400 Received: from cavan.codon.org.uk ([93.93.128.6]:54575 "EHLO cavan.codon.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754882Ab0ECVjo (ORCPT ); Mon, 3 May 2010 17:39:44 -0400 Date: Mon, 3 May 2010 22:39:19 +0100 From: Matthew Garrett To: Kevin Hilman Cc: Jonathan Corbet , mgross@linux.intel.com, aili@codeaurora.org, dwalker@codeaurora.org, tiwai@suse.de, bruce.w.allan@intel.com, davidb@quicinc.com, mcgrof@gmail.com, pavel@ucw.cz, linux-pm , lkml Subject: Re: [PATCH]PM QOS refresh against next-20100430 Message-ID: <20100503213919.GA18910@srcf.ucam.org> References: <20100430212043.GA30315@linux.intel.com> <20100503103300.6330e522@bike.lwn.net> <87y6g1547o.fsf@deeprootsystems.com> <20100503104250.7605d2bc@bike.lwn.net> <87tyqo537l.fsf@deeprootsystems.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87tyqo537l.fsf@deeprootsystems.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: mjg59@cavan.codon.org.uk X-SA-Exim-Scanned: No (on cavan.codon.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 03, 2010 at 10:01:50AM -0700, Kevin Hilman wrote: > Jonathan Corbet writes: > > Well, shallow could mean that the state lacks the CPUIDLE_FLAG_DEEP > > flag; that should be relatively portable. In any case, it seems > > more so than "if I put in a 55us latency requirement, I'll stay out > > of C3". > > I guess it depends on your goal. Do you just want to stay out of C3 > on your current platform? or do you want to stay out of any low-power > state (on any platform) where you'll have a latency of > 55 usecs? I'd say that one plausible requirement is "DMA works", with another being "all interrupts work" as distinguished from "wakeup interrupts work". -- Matthew Garrett | mjg59@srcf.ucam.org