Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753201AbYCJMvd (ORCPT ); Mon, 10 Mar 2008 08:51:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751260AbYCJMvZ (ORCPT ); Mon, 10 Mar 2008 08:51:25 -0400 Received: from gateway.drzeus.cx ([85.8.24.16]:50631 "EHLO smtp.drzeus.cx" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751185AbYCJMvY (ORCPT ); Mon, 10 Mar 2008 08:51:24 -0400 Date: Mon, 10 Mar 2008 13:49:15 +0100 From: Pierre Ossman To: Pavel Machek Cc: LKML , linux-pm@lists.linux-foundation.org, "Pallipadi, Venkatesh" , Dave Jones , Andi Kleen , Alan Stern , Adam Belay , Lee Revell Subject: Re: [linux-pm] [PATCH] cpuidle: avoid singing capacitors Message-ID: <20080310134915.45ae7446@mjolnir.drzeus.cx> In-Reply-To: <20080310100008.GA9520@elf.ucw.cz> References: <20080303231033.GB15255@one.firstfloor.org> <20080304040048.GA31562@codemonkey.org.uk> <20080304071423.0e6b71c1@mjolnir.drzeus.cx> <20080304181924.70aaf8c1@mjolnir.drzeus.cx> <924EFEDD5F540B4284297C4DC59F3DEEA77031@orsmsx423.amr.corp.intel.com> <20080305070201.0d16cd40@mjolnir.drzeus.cx> <20080305094023.6486ebdf@mjolnir.drzeus.cx> <20080306092730.4412d085@mjolnir.drzeus.cx> <20080309151659.63d54f38@mjolnir.drzeus.cx> <20080310100008.GA9520@elf.ucw.cz> X-Mailer: Claws Mail 3.3.1 (GTK+ 2.12.8; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1292 Lines: 34 On Mon, 10 Mar 2008 11:00:08 +0100 Pavel Machek wrote: > On Sun 2008-03-09 15:16:59, Pierre Ossman wrote: > > 2. uhci_hcd driver > > > > USB is somehow involved in this problem. Unloading the uhci_hcd driver almost entirely kills the noise on a 1000 HZ NO_HZ kernel. On a 100 HZ, no NO_HZ kernel, the effect is very small, but still there. > > USB keeps processor out of C3 in many cases. > I figured that was the case. But I did not see any difference in powertop. > > 4. Battery and AC > > > > The noise increases with the battery present and also when the AC supply is removed. > > > > On battery, some machines swap C3 for "secret" C4, which is slower but > saves power. I guess the only way to find out is to disassemble the DSDT. Exposing myself to such concentrations of ACPI is not an appealing project. :/ -- -- Pierre Ossman Linux kernel, MMC maintainer http://www.kernel.org PulseAudio, core developer http://pulseaudio.org rdesktop, core developer http://www.rdesktop.org -- 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/