From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758350AbYGXPNh (ORCPT ); Thu, 24 Jul 2008 11:13:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754157AbYGXPNY (ORCPT ); Thu, 24 Jul 2008 11:13:24 -0400 Received: from dgate10.fujitsu-siemens.com ([80.70.172.49]:35190 "EHLO dgate10.fujitsu-siemens.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757553AbYGXPNX (ORCPT ); Thu, 24 Jul 2008 11:13:23 -0400 DomainKey-Signature: s=s768; d=fujitsu-siemens.com; c=nofws; q=dns; h=X-SBRSScore:X-IronPort-AV:Received:X-IronPort-AV: Received:Received:Message-ID:Date:From:Organization: User-Agent:MIME-Version:To:CC:Subject:References: In-Reply-To:Content-Type:Content-Transfer-Encoding; b=NAimO3Wj7geGscrQgCbd0V438Dm4FXXWiIByyd5nI+POEQyEUlevyO0w VxlaoH0ZC0US1Og7XVH6/tU7dtsCGODI0aLrvQsW2tx0dSoXny5gpZjlr KVOZwzsvbaQdN5F; X-SBRSScore: None X-IronPort-AV: E=Sophos;i="4.31,246,1215381600"; d="scan'208";a="23425126" X-IronPort-AV: E=Sophos;i="4.31,245,1215381600"; d="scan'208";a="36323316" Message-ID: <48889C14.4070408@fujitsu-siemens.com> Date: Thu, 24 Jul 2008 17:13:24 +0200 From: Martin Wilck Organization: Fujitsu Siemens Computers User-Agent: Thunderbird 2.0.0.15pre (X11/20080508) MIME-Version: 1.0 To: Cyrill Gorcunov CC: Thomas Gleixner , "linux-kernel@vger.kernel.org" , "H. Peter Anvin" , "Wichert, Gerhard" , "Maciej W. Rozycki" Subject: Re: [PATCH] x86 (64): make calibrate_APIC_clock() SMI-safe References: <48885DDC.9010003@fujitsu-siemens.com> <20080724111631.GA3432@lenovo> <48886E6D.1030005@fujitsu-siemens.com> <20080724120512.GA21804@lenovo> <488889B6.9070707@fujitsu-siemens.com> <20080724143151.GA32422@lenovo> <20080724150116.GC32422@lenovo> In-Reply-To: <20080724150116.GC32422@lenovo> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Cyrill, > btw, Martin, don't get me wrong please - i'm not just complaining :) > The changes you propose is important enough _but_ it could introduce > regression. Look, with situation of miscalibrated apic timer kernel > was working before but with the patch it could stop to work. So if > user has a such screwed motherboard he could be shocked if it stop > booting with message about SMI happened. we defenitely have to provide > some workaround for this. And your max iteration counter solution > would be fine I think. Let's see what other people think about this. I am fine with both solutions. Currently only the first one has been tested though (testing these patches thoroughly needs long-time reboot tests). One more remark: There are similar calibration routines around in the kernel which suffer from similar problems as calibrate_APIC_clock(). AFAIK, only calibrate_delay() was made SMI-safe by Venkatesh Pallipadi years ago. Martin -- Martin Wilck PRIMERGY System Software Engineer FSC IP ESP DEV 6 Fujitsu Siemens Computers GmbH Heinz-Nixdorf-Ring 1 33106 Paderborn Germany Tel: ++49 5251 8 15113 Fax: ++49 5251 8 20209 Email: mailto:martin.wilck@fujitsu-siemens.com Internet: http://www.fujitsu-siemens.com Company Details: http://www.fujitsu-siemens.com/imprint.html