From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751248AbWDYBzL (ORCPT ); Mon, 24 Apr 2006 21:55:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751515AbWDYBzL (ORCPT ); Mon, 24 Apr 2006 21:55:11 -0400 Received: from fmr20.intel.com ([134.134.136.19]:59012 "EHLO orsfmr005.jf.intel.com") by vger.kernel.org with ESMTP id S1751248AbWDYBzJ convert rfc822-to-8bit (ORCPT ); Mon, 24 Apr 2006 21:55:09 -0400 Subject: Re: 2.6.17-rc1: kernel only boots one CPU on HT system From: Shaohua Li To: Kevin Baradon Cc: Andrew Morton , linux-kernel@vger.kernel.org In-Reply-To: <200604241926.25239.Kevin.Baradon@gmail.com> References: <200604231434.59966.Kevin.Baradon@gmail.com> <20060423141519.314ae567.akpm@osdl.org> <1145843859.19994.63.camel@sli10-desk.sh.intel.com> <200604241926.25239.Kevin.Baradon@gmail.com> Content-Type: text/plain; charset=UTF-8 Date: Tue, 25 Apr 2006 09:53:48 +0800 Message-Id: <1145930028.19994.68.camel@sli10-desk.sh.intel.com> Mime-Version: 1.0 X-Mailer: Evolution 2.2.2 (2.2.2-5) Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2006-04-24 at 19:26 +0200, Kevin Baradon wrote: > Le Lundi 24 Avril 2006 03:57, Shaohua Li a écrit : > > Hi, > > Hello, > > > > On Sun, 2006-04-23 at 14:15 -0700, Andrew Morton wrote: > > > Kevin Baradon wrote: > > > > Hello, > > > > > > > > Starting with kernel 2.6.17-rc1 (also happens with 2.6.17-rc2), second > > > > logical-CPU of my Hyperthreading system no longer boots. > > > > > > > > I tracked up changes in APIC code, and it appears reverting commit > > > > 7c5c1e427b5e83807fd05419d1cf6991b9d87247 fixes this bug. > > > > > > That helps heaps, thanks. > > > > The commit doesn't look like the root cause to me. BIOS already assigns > > unique id to ioapic, and the cpu family is 15, so with/without the patch > > the code path hasn't any difference. Kevin, can you please make a clean > > build and check if the patch is the real cause? > > > > You were right. Reverting this commit helps sometimes, but doesn't work > reliably. When my computer booted this morning, I've had only one CPU > detected. I've tried booting several times, even with a complete power down. > Nothing changed. > > I've also tried with kernel 2.6.16-rc6, which booted fine and detected two > CPUs. > > I've applied your small patch. Debugging output is attached. > > If you want, I can apply this small patch also to kernel 2.6.16-rc6, and send > you debugging output. > > > If it still doesn't work, you might apply a small change below to > > include/asm-i386/apic.h, and attach the dmesg, so we could analyze it. > > > > File attached. The CPU doesn't startup. Sometime ago somebody reported a similar issue for 2.6.16.1. But the failure isn't reliably triggered. IIRC, there isn't a solution. Thanks, Shaohua