Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751828AbVLGXfA (ORCPT ); Wed, 7 Dec 2005 18:35:00 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751812AbVLGXe7 (ORCPT ); Wed, 7 Dec 2005 18:34:59 -0500 Received: from www.eclis.ch ([144.85.15.72]:60561 "EHLO mail.eclis.ch") by vger.kernel.org with ESMTP id S1751828AbVLGXe6 (ORCPT ); Wed, 7 Dec 2005 18:34:58 -0500 Message-ID: <439771A0.1000604@eclis.ch> Date: Thu, 08 Dec 2005 00:34:56 +0100 From: Jean-Christian de Rivaz User-Agent: Mozilla Thunderbird 1.0.2 (X11/20051002) X-Accept-Language: fr, en MIME-Version: 1.0 To: Gene Heskett Cc: linux-kernel@vger.kernel.org Subject: Re: ntp problems References: <200512050031.39438.gene.heskett@verizon.net> <200512070108.58466.gene.heskett@verizon.net> <43975A96.9090503@eclis.ch> <200512071750.20709.gene.heskett@verizon.net> In-Reply-To: <200512071750.20709.gene.heskett@verizon.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1652 Lines: 44 Gene Heskett a ?crit : > On Wednesday 07 December 2005 16:56, Jean-Christian de Rivaz wrote: > >>Gene Heskett a ?crit : >> >>>And, acpi is on, and ntpd is happy with the new bios. Hurrah! >> >>Good news! >> >>I wonder if it would be a good idea to add something into the kernel or >>into ntpd to alert the users that ntpd can't run normaly because of a >>too fast drift ? Then a BIOS upgrade could be proposed (especially on a >>nForce2 system). I don't know if it's even realistc. >> >>Regards, > > > The drift itself wasn't what I'd call excessive, > something like 6 minutes in a week, which for > mainboard quality crystals is pretty darned good. ntpd work only on system with a drift of maximum +/-500ppm. This post summarize a lot of informations about the problem: http://marc.theaimsgroup.com/?l=linux-kernel&m=113105244509795&w=2 It was found later that an issue into the nForce2 is the root of the problem and that a BIOS update solve it. 6.0 / (60*24*7) * 1e6 = 595.24 6 minutes per week is near 600ppm, it's enough to trigg the problem you have seen. Even very cheap crystal are 100ppm at commercial temperature range. 100ppm is about 1 minute per week. Some crystal manufacturers propose now 30ppm as the default standard at commercial temperature range. As your watch prove, good cristal can be just a few ppm (about 3.86ppm for your watch) Regards, -- Jean-Christian de Rivaz - 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/