From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752677AbbAUJdt (ORCPT ); Wed, 21 Jan 2015 04:33:49 -0500 Received: from www.linutronix.de ([62.245.132.108]:53209 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750926AbbAUJdk (ORCPT ); Wed, 21 Jan 2015 04:33:40 -0500 Date: Wed, 21 Jan 2015 10:33:19 +0100 (CET) From: Thomas Gleixner To: Jiang Liu cc: LKML , Joerg Roedel , x86@kernel.org, Tony Luck , Borislav Petkov Subject: Re: [patch 00/23] x86: Cleanup apic/ioapic/x2apic setup code In-Reply-To: <54BF05CA.9070506@linux.intel.com> Message-ID: References: <20150115210458.625399149@linutronix.de> <54B8DBC1.6080205@linux.intel.com> <54BF05CA.9070506@linux.intel.com> User-Agent: Alpine 2.11 (DEB 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 21 Jan 2015, Jiang Liu wrote: > On 2015/1/16 19:05, Thomas Gleixner wrote: > Hi Thomas, > With above patch applied, it just gives a blank screen > instead of a panic when booting on my problematic laptop. > Now I have found the root cause of the failure on my laptop. > On i386, it triggers BUG_ON(!apic->apic_id_registered()) > in function setup_local_APIC() because apic_bsp_up_setup() is called > too late. So we need a simple patch as below. With following patch > applied, it boots successfully with your original patch. Duh. Right you are. I wonder why this boots on any other machine. Seems there is some more magic in this setup maze. Thanks, tglx