Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757407AbXIFLb7 (ORCPT ); Thu, 6 Sep 2007 07:31:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753322AbXIFLbw (ORCPT ); Thu, 6 Sep 2007 07:31:52 -0400 Received: from ns.suse.de ([195.135.220.2]:47318 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752101AbXIFLbw (ORCPT ); Thu, 6 Sep 2007 07:31:52 -0400 To: Chuck Ebbert Cc: linux-kernel Subject: Re: Why do so many machines need "noapic"? References: <46DF3BFF.9000809@redhat.com> From: Andi Kleen Date: 06 Sep 2007 13:31:50 +0200 In-Reply-To: <46DF3BFF.9000809@redhat.com> Message-ID: User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.3 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1111 Lines: 27 Chuck Ebbert writes: > Some systems lock up without the noapic option. Please find patterns: cpu type, chipsets, mainboard vendors etc. > I found one > that will freeze while trying to set up the timer interrupt. > Passing 'nolapic' makes it freeze just after: > > Setting up timer through ExtINT... works Always boot with apic=debug The messages means the primary timer setup methods already didn't work. ExtInt is really a crappy fallback that was originally only needed for some early SMP systems which where the timer was not wired according to specs. But the real problem is that the standard timer access method through the local APIC didn't work. I had a rewrite of the timer probing some time ago that tried more combinations automatically. It had some problems so it never went in, but perhaps it's worth revisiting. -Andi - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/