Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759591Ab3HNJgR (ORCPT ); Wed, 14 Aug 2013 05:36:17 -0400 Received: from 8bytes.org ([85.214.48.195]:50089 "EHLO mail.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754972Ab3HNJgP (ORCPT ); Wed, 14 Aug 2013 05:36:15 -0400 Date: Wed, 14 Aug 2013 11:36:12 +0200 From: Joerg Roedel To: Guenter Roeck Cc: Bjorn Helgaas , "linux-kernel@vger.kernel.org" , "open list:INTEL IOMMU (VT-d)" , David Woodhouse Subject: Re: WARNING: at drivers/iommu/dmar.c:484 warn_invalid_dmar with Intel Motherboard Message-ID: <20130814093607.GB4491@8bytes.org> References: <20130709202406.GA11867@roeck-us.net> <20130709223106.GA16429@roeck-us.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130709223106.GA16429@roeck-us.net> User-Agent: Mutt/1.5.21 (2010-09-15) X-DSPAM-Result: Whitelisted X-DSPAM-Processed: Wed Aug 14 11:36:14 2013 X-DSPAM-Confidence: 0.9981 X-DSPAM-Probability: 0.0000 X-DSPAM-Signature: 520b4f8e20861707060788 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1227 Lines: 32 On Tue, Jul 09, 2013 at 03:31:06PM -0700, Guenter Roeck wrote: > On Tue, Jul 09, 2013 at 03:05:39PM -0600, Bjorn Helgaas wrote: > > [+cc Joerg, David, iommu list] > > > > On Tue, Jul 9, 2013 at 2:24 PM, Guenter Roeck wrote: > > > I started seeing this problem after updating the BIOS trying fix another issue, > > > though I may have missed it earlier. > > > > > > I understand this is a BIOS bug. Would be great if someone can pass this on > > > to Intel BIOS engineers. > > > > Maybe. It'd be nice if Linux handled it better, though. > > > If anyone has an idea how to do that, I'll be happy to write a patch. I doubt that we can do anything meaningful here. The BIOS is broken in a way so that we can't use the IOMMU in Linux. We can patch away the WARN_ON and make it a sumple FW_BUG message, but the noise a WARN_ON makes maybe help getting this issue fixed. But I may be convinced otherwise, if people think this WARN_ON is not worth it. Joerg -- 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/