From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752116Ab2LQJfB (ORCPT ); Mon, 17 Dec 2012 04:35:01 -0500 Received: from mailgw1.uni-kl.de ([131.246.120.220]:37575 "EHLO mailgw1.uni-kl.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751536Ab2LQJfA (ORCPT ); Mon, 17 Dec 2012 04:35:00 -0500 Message-ID: <50CEE736.8020000@itwm.fraunhofer.de> Date: Mon, 17 Dec 2012 10:34:46 +0100 From: Bernd Schubert User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: Borislav Petkov , Yinghai Lu , Ingo Molnar , linux-kernel@vger.kernel.org, Weidong Han , David Woodhouse Subject: Re: [regression] 3.7 ends in APIC panic References: <50CB3EAB.309@itwm.fraunhofer.de> <50CE0C82.20708@itwm.fraunhofer.de> <50CE12EB.1050804@itwm.fraunhofer.de> <20121216191347.GB14678@liondog.tnic> <50CE24FE.3030409@itwm.fraunhofer.de> <20121216203913.GB14643@liondog.tnic> In-Reply-To: <20121216203913.GB14643@liondog.tnic> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-ITWM-CharSet: UTF-8 X-ITWM-Scanned-By: mail2.itwm.fhg.de Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/16/2012 09:39 PM, Borislav Petkov wrote: > On Sun, Dec 16, 2012 at 08:46:06PM +0100, Bernd Schubert wrote: >> Hmm, I read it the other way around - x2apic depends on interrupt >> remapping, but interrupt remapping can be used without x2apic. > > Ok, you're right. X2APIC should depend on IRQ_REMAP: > https://lwn.net/Articles/289881/ > >> The help text of CONFIG_IRQ_REMAP also says "x2APIC enhancements or to >> support platforms with CPU's having > 8 bit APIC ID, say Y." I guess >> may CPU has the latter? > > I think it is what Yinghai said - you obviously need x2apic kernel > support if you have IRQ_REMAP on. > >> Can the kernel panic a bit improved to help user to understand what >> needs to be enabled? > > Well, your kernel enables IRQ_REMAP properly: > > [ 0.031115] Enabled IRQ remapping in x2apic mode > > I guess at that stage we could probably check for x2apic support and > scream loudly if it is not present... IMHO. > Hmm, I think that would the wrong place, as the initial 3.7.0 configuration didn't have IRQ_REMAP enabled. And that was the reason why x2apic got disabled during the "make oldconfig" process... Is this message an indication for missing x2apic? "smpboot: weird, boot (#255) not listed by the BIOS" Thanks, Bernd