Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762751AbZAWLF0 (ORCPT ); Fri, 23 Jan 2009 06:05:26 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755722AbZAWLFM (ORCPT ); Fri, 23 Jan 2009 06:05:12 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:47483 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755316AbZAWLFK (ORCPT ); Fri, 23 Jan 2009 06:05:10 -0500 Date: Fri, 23 Jan 2009 12:04:39 +0100 From: Ingo Molnar To: john stultz Cc: Miklos Vajna , Florian Fainelli , linux-kernel@vger.kernel.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , "Rafael J. Wysocki" , Gabriel C , =?iso-8859-1?Q?CS=C9CSY_L=E1szl=F3?= Subject: Re: System clock runs too fast after 2.6.27 -> 2.6.28.1 upgrade Message-ID: <20090123110439.GK15188@elte.hu> References: <20090121171423.GI21473@genesis.frugalware.org> <1f1b08da0901211200l88fa89s78a51c4e90878d85@mail.gmail.com> <20090121210726.GK21473@genesis.frugalware.org> <1232573646.6997.21.camel@localhost.localdomain> <20090122195132.GZ21473@genesis.frugalware.org> <20090122235727.GB21473@genesis.frugalware.org> <1232674994.6678.45.camel@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1232674994.6678.45.camel@localhost.localdomain> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1822 Lines: 44 * john stultz wrote: > On Fri, 2009-01-23 at 00:57 +0100, Miklos Vajna wrote: > > On Thu, Jan 22, 2009 at 12:03:14PM -0800, john stultz > > > CONFIG_X86_VISWS: If I recall, this is support for SGI workstations that > > > had different apics then most systems, and might be related. > > > > > I just did a new build with CONFIG_X86_VISWS and CONFIG_X86_RDC321X > > disabled, but I kept CONFIG_PARAVIRT_GUEST enabled and that works fine > > as well. So CONFIG_PARAVIRT_GUEST seems to be unrelated. > > Ah. CONFIG_X86_RDC321X is indeed the issue. > > >From arch/x86/include/asm/timex.h: > > #ifdef CONFIG_X86_ELAN > # define PIT_TICK_RATE 1189200 /* AMD Elan has different frequency! */ > #elif defined(CONFIG_X86_RDC321X) > # define PIT_TICK_RATE 1041667 /* Underlying HZ for R8610 */ > #else > # define PIT_TICK_RATE 1193182 /* Underlying HZ */ > #endif > > This gives the kernel an incorrect slower frequency for the PIT hardware > on your system and is why the TSC calibration is off and why the ACPI PM > gets thrown out. > > I'd think this would ideally be more of a subarch in the config > selection like the AMD Elan is, so folks know it really is not just a > extra-support feature and in fact limits what hardware you can use the > resulting kernel on. a better solution is that if RDC is set [it is unset by default] we should turn PIT_TICK_RATE into a variable, defaulting it to 1193182. If a real RDC or ELAN system is running, that variable is changed during early bootup, in the init functions for those platforms. Ingo -- 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/