From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758358AbZHQXWp (ORCPT ); Mon, 17 Aug 2009 19:22:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758285AbZHQXWo (ORCPT ); Mon, 17 Aug 2009 19:22:44 -0400 Received: from solitude.tty.gr ([95.154.208.37]:52207 "EHLO mx.tty.gr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751238AbZHQXWo (ORCPT ); Mon, 17 Aug 2009 19:22:44 -0400 Message-ID: <4A89E63E.407@debian.org> Date: Tue, 18 Aug 2009 02:22:38 +0300 From: Faidon Liambotis Organization: Debian User-Agent: Mozilla-Thunderbird 2.0.0.22 (X11/20090707) MIME-Version: 1.0 To: Chris Wright CC: linux-kernel@vger.kernel.org, Suresh Siddha , iommu@lists.linux-foundation.org, David Woodhouse Subject: Re: [regression, bisected] fails to boot on Dell Optiplex 760 with VT-d enabled References: <4A89CB52.4030008@debian.org> <20090817231156.GJ24885@sequoia.sous-sol.org> In-Reply-To: <20090817231156.GJ24885@sequoia.sous-sol.org> 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 Chris Wright wrote: > AFAIK, this platform is broken when VT-d is enabled. > Can you add this patch to a broken kernel and retest? > Please boot with 'debug' on the kernel command line. Thanks but David was faster, we've already established that http://git.infradead.org/iommu-2.6.git/commit/0815565a which is, as far as I can understand, very similar to your patch, indeed fixes the issue. > + if (ver == (u32)-1 || iommu->cap == (u64)-1 || iommu->ecap == (u64)-1) { As an observation, David's patch is checking if *both* iommu->cap and iommu->ecap are -1, while yours checks for either. You're also checking for ver. Obviously, I have no idea which of the two is more correct. Thanks, Faidon