From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752779AbaCJK1h (ORCPT ); Mon, 10 Mar 2014 06:27:37 -0400 Received: from cpsmtpb-ews05.kpnxchange.com ([213.75.39.8]:54199 "EHLO cpsmtpb-ews05.kpnxchange.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752138AbaCJK1g (ORCPT ); Mon, 10 Mar 2014 06:27:36 -0400 Message-ID: <1394447253.2979.12.camel@x220> Subject: Re: [RESEND] Fast TSC calibration fails with v3.14-rc1 and later From: Paul Bolle To: Julian Wollrath Cc: x86@kernel.org, linux-kernel@vger.kernel.org Date: Mon, 10 Mar 2014 11:27:33 +0100 In-Reply-To: <20140310110410.5b2218f6@ilfaris> References: <20140310110410.5b2218f6@ilfaris> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.4 (3.10.4-2.fc20) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 10 Mar 2014 10:27:34.0411 (UTC) FILETIME=[59D0E5B0:01CF3C4B] X-RcptDomain: vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2014-03-10 at 11:04 +0100, Julian Wollrath wrote: > on a Thinkpad x121e (AMD E-450 APU) with version 3.13.5 and earlier of > the kernel I get: > [...] > [ 0.000000] tsc: Fast TSC calibration using PIT > [ 0.001000] tsc: Detected 1646.619 MHz processor > [ 0.000004] Calibrating delay loop (skipped), value calculated using > timer frequency.. 3293.23 BogoMIPS (lpj=1646619) > [...] > > > but starting with v3.14-rc1 the fast TSC calibration fails: > [...] > [ 0.000000] tsc: Fast TSC calibration failed > [ 0.000000] tsc: PIT calibration matches HPET. 1 loops > [ 0.000000] tsc: Detected 1646.490 MHz processor > [...] > > If you need more information, please do not hesitate to ask. I submitted a patch to downgrade the "Fast TSC calibration failed" message to KERN_INFO level, see https://lkml.org/lkml/2012/9/26/131 . That patch was basically ignored. I've carried it locally ever since. So the error need not be v3.14-rc1 specific. But perhaps something changed in v3.14-rc1 that makes it easier to trigger that error. I haven't checked. (I wrote some notes on this issue in https://lkml.org/lkml/2012/9/24/221 , perhaps they might be of help.) Paul Bolle