From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758186AbZHQWEL (ORCPT ); Mon, 17 Aug 2009 18:04:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753931AbZHQWEK (ORCPT ); Mon, 17 Aug 2009 18:04:10 -0400 Received: from solitude.tty.gr ([95.154.208.37]:56282 "EHLO mx.tty.gr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752630AbZHQWEJ (ORCPT ); Mon, 17 Aug 2009 18:04:09 -0400 X-Greylist: delayed 2175 seconds by postgrey-1.27 at vger.kernel.org; Mon, 17 Aug 2009 18:04:09 EDT Message-ID: <4A89CB52.4030008@debian.org> Date: Tue, 18 Aug 2009 00:27:46 +0300 From: Faidon Liambotis Organization: Debian User-Agent: Mozilla-Thunderbird 2.0.0.22 (X11/20090707) MIME-Version: 1.0 To: linux-kernel@vger.kernel.org CC: Suresh Siddha , Weidong Han , David Woodhouse , iommu@lists.linux-foundation.org, allen.m.kay@intel.com, fenghua.yu@intel.com Subject: [regression, bisected] fails to boot on Dell Optiplex 760 with VT-d enabled X-Enigmail-Version: 0.95.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. I ran git bisect good v2.6.30/bad v2.6.31-rc1 and I was pointed to the following commit: 937582382c71b75b29fbb92615629494e1a05ac0 x86, intr-remap: enable interrupt remapping early I have no idea if VT-d is functioning on v2.6.30; I just had the option enabled in the BIOS and noticed the problem when I tried to upgrade to 2.6.31-rcX. I've read a similar bug report against a Mandriva kernel and another VT-d related bug for the same hardware against Xen and in both threads they were finger-pointing the BIOS. I'm not sure if that's the case but, even if it is, I'd expect the system to boot, like previous versions did, perhaps printing a warning about VT-d functionality. Thanks, Faidon