From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751401AbZITElI (ORCPT ); Sun, 20 Sep 2009 00:41:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750848AbZITElI (ORCPT ); Sun, 20 Sep 2009 00:41:08 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:43087 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750819AbZITElH (ORCPT ); Sun, 20 Sep 2009 00:41:07 -0400 Subject: Re: Current git fails to boot with VT-D enabled due to flood of DMAR errors From: David Woodhouse To: Robert Hancock Cc: linux-kernel In-Reply-To: <4AB5B07B.5090506@gmail.com> References: <4AB5B07B.5090506@gmail.com> Content-Type: text/plain Date: Sat, 19 Sep 2009 21:41:08 -0700 Message-Id: <1253421668.6317.83.camel@macbook.infradead.org> Mime-Version: 1.0 X-Mailer: Evolution 2.26.3 (2.26.3-1.fc11) Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2009-09-19 at 22:32 -0600, Robert Hancock wrote: > On an Asus P7P55D Pro-based system (Lynnfield CPU), with Intel VT-d > enabled in the BIOS, on 2.6.30.5 (the previous version I tested) I get > these lines in dmesg: > > DMAR:Host address width 36 > DMAR:DRHD (flags: 0x00000001)base: 0x00000000fed90000 > DMAR:RMRR base: 0x00000000000e4000 end: 0x00000000000e7fff > DMAR:RMRR base: 0x00000000bf7ec000 end: 0x00000000bf7fffff > Not all IO-APIC's listed under remapping hardware > > In current -git, I get these lines as well, but then I get this: > > DRHD: handling fault status reg ffffffff > DMAR:[DMA Read] Request device [ff:1f.7] fault addr fffffffffffff000 > DMAR:[fault reason 255] Unknown > > The last two lines repeat in a continuous flood and the system doesn't > boot. This happens even if I pass "intel_iommu=off" (which seems like > it's already the default). > > Could be a kernel bug or a BIOS bug, but in the latter case we should > probably deal with it better. The registers all reading FF seems like > maybe the registers are disabled or something.. This ought to be 'fixed' in linux-next by this commit: http://git.infradead.org/iommu-2.6.git/commitdiff/0815565ad Please try linux-next or the iommu tree from git://git.infradead.org/iommu-2.6.git -- David Woodhouse Open Source Technology Centre David.Woodhouse@intel.com Intel Corporation