From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755857AbZHQWRI (ORCPT ); Mon, 17 Aug 2009 18:17:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752055AbZHQWRH (ORCPT ); Mon, 17 Aug 2009 18:17:07 -0400 Received: from mga03.intel.com ([143.182.124.21]:60403 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750907AbZHQWRG (ORCPT ); Mon, 17 Aug 2009 18:17:06 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.43,398,1246863600"; d="scan'208";a="176757049" Subject: Re: [regression, bisected] fails to boot on Dell Optiplex 760 with VT-d enabled From: David Woodhouse To: Faidon Liambotis Cc: "linux-kernel@vger.kernel.org" , "Siddha, Suresh B" , "Han, Weidong" , "iommu@lists.linux-foundation.org" , "Kay, Allen M" , "Yu, Fenghua" In-Reply-To: <4A89CB52.4030008@debian.org> References: <4A89CB52.4030008@debian.org> Content-Type: text/plain Organization: Intel Corporation. Pipers Way, Swindon, Wiltshire, SN3 1RJ, UK. Date: Mon, 17 Aug 2009 23:17:03 +0100 Message-Id: <1250547423.7405.362.camel@macbook.infradead.org> Mime-Version: 1.0 X-Mailer: Evolution 2.26.3 (2.26.3-1.fc11) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2009-08-17 at 14:27 -0700, Faidon Liambotis wrote: > I am experiencin a bug on an Dell Optiplex 760 with a configuration that > has an Intel Core2 Q9550 CPU and with an up-to-date BIOS, version A03. > > When "VT for Direct I/O" is enabled in the BIOS, v2.6.30 boots and works > perfectly, while v2.6.31-rc1..rc6 fail (both of them x86-64). > > More specifically, I get an endless loop of printing the following > messages in > the screen: > DMAR: [DMA Read] Request device [ff:1f.7] fault addr > fffffffffffff000 > DMAR: [fault reason 255] Unknown > and the boot process doesn't move on from there. Is it fixed by http://git.infradead.org/iommu-2.6.git/commit/0815565a ? I strongly suspect you weren't actually using the IOMMU in your 'working' 2.6.30 kernel? Can you show a full log of that one booting? -- David Woodhouse Open Source Technology Centre David.Woodhouse@intel.com Intel Corporation