From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932501AbZHDHJ5 (ORCPT ); Tue, 4 Aug 2009 03:09:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932476AbZHDHJ4 (ORCPT ); Tue, 4 Aug 2009 03:09:56 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:50509 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932474AbZHDHJz (ORCPT ); Tue, 4 Aug 2009 03:09:55 -0400 Subject: Re: [RFC patch] return early if all dmar HW unit ignored From: David Woodhouse To: Luming Yu Cc: LKML In-Reply-To: <3877989d0907310129p29dd5039p18563946b9be8099@mail.gmail.com> References: <3877989d0907310129p29dd5039p18563946b9be8099@mail.gmail.com> Content-Type: text/plain Date: Tue, 04 Aug 2009 08:09:54 +0100 Message-Id: <1249369794.9324.18.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 Fri, 2009-07-31 at 16:29 +0800, Luming Yu wrote: > Hello list, > > When debugging an IOMMU problem, I noticed it should be much more safe > to return early than late if all remapping HW unit are ignored. > To figure out what device causes the iommu problem on my linux box: > hp-compaq dc7800, I tried to mark all dmar HW > unit ignored,but still got a lot of unxepcted dmar_fault. So I think > the proposed patch make sense. The next step is to > add a boot option to make dmar HW units selectable enable/disable individually. Why were you seeing faults if all dmar units were ignored? Surely that shouldn't happen? This patch doesn't make a lot of sense on its own -- can you show what you were intending to do as the 'next step'? -- David Woodhouse Open Source Technology Centre David.Woodhouse@intel.com Intel Corporation