From mboxrd@z Thu Jan 1 00:00:00 1970 From: Timo Hoenig Subject: Re: [PATCH 2.6.18 1/1] ACPI: limit cstate on noisy thinkpad t43/p models Date: Mon, 25 Sep 2006 15:50:08 +0200 Message-ID: <1159192208.4475.9.camel@nouse.suse.de> References: <1159097883.5437.12.camel@nouse.suse.de> <200609250306.31350.len.brown@intel.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from ns1.suse.de ([195.135.220.2]:23438 "EHLO mx1.suse.de") by vger.kernel.org with ESMTP id S1750817AbWIYJFB (ORCPT ); Mon, 25 Sep 2006 05:05:01 -0400 In-Reply-To: <200609250306.31350.len.brown@intel.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Len Brown Cc: shadow@serverart.org, linux-acpi@vger.kernel.org Hi, On Mon, 2006-09-25 at 03:06 -0400, Len Brown wrote: > On Sunday 24 September 2006 07:38, Timo Hoenig wrote: > > > I think it is a more general problem. The systems with Intel Core Duo I > > got my hands on all show the symptom: Once the system is idle, the > > second core begins to whine. It's annoying in quiet environments. > > > > * Turning off the second core makes the whining stop. > > * Booting with processor.max_cstate=2 does also make the whining > > go away; but it's a bad idea on laptops if once wants to gain a > > long run on batteries. > > > > Tested with HZ=250; I'll check whether HZ=100/1000 helps. > > Curious, I have not noticed this on the Core Duo systems I have. > > In the past this has been traced to the voltage switching on the motherboard > causing the capacitors to vibrate and the motherboard to resonate. > That is why changing HZ will likely have an effect on the problem. Yes, that's what I have found to be the culprit, too. Sorry that I do not have yet been able to check with different HZ than 250 so far. > Exactly what model system do you have that is making noise? * Lenovo ThinkPad T60, several different models * Fujitsu Siemens e8110 Also, I just got my hands on a Lenovo ThinkPad X60 and ran the same test [1] as on the other machines but did not hear any noise. Timo [1] Test with Linux 2.6.18-rc6 (with pwd /sys/devices/system/cpu/cpu1) while (true); do echo 0 > online; sleep 1; echo 1 > online; sleep 1; done;