From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758353AbYGKAAa (ORCPT ); Thu, 10 Jul 2008 20:00:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755520AbYGKAAS (ORCPT ); Thu, 10 Jul 2008 20:00:18 -0400 Received: from mga10.intel.com ([192.55.52.92]:51392 "EHLO fmsmga102.fm.intel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755517AbYGKAAQ (ORCPT ); Thu, 10 Jul 2008 20:00:16 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.30,341,1212390000"; d="scan'208";a="589716598" Date: Thu, 10 Jul 2008 19:53:26 -0400 From: Yong Wang To: Andrew Morton Cc: Yong Wang , linux-kernel@vger.kernel.org, suresh.b.siddha@intel.com Subject: Re: [PATCH] Intel IOMMU: RMRRs do not necessarily have to be present on all VT-d capable platforms Message-ID: <20080710235326.GA21208@ywang-dev> References: <20080701091354.GA12969@ywang-dev> <20080710010149.a73d779c.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080710010149.a73d779c.akpm@linux-foundation.org> User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 10, 2008 at 01:01:49AM -0700, Andrew Morton wrote: > On Tue, 1 Jul 2008 05:13:54 -0400 Yong Wang wrote: > > > RMRRs do not necessarily have to be present on all VT-d capable platforms. > > The printk is just informational and does not need to be followed by an > > error return. > > > > Signed-off-by: Yong Y Wang > > --- > > dmar.c | 4 +--- > > 1 file changed, 1 insertion(+), 3 deletions(-) > > > > diff --git a/drivers/pci/dmar.c b/drivers/pci/dmar.c > > index f941f60..8bf86ae 100644 > > --- a/drivers/pci/dmar.c > > +++ b/drivers/pci/dmar.c > > @@ -317,10 +317,8 @@ int __init dmar_table_init(void) > > return -ENODEV; > > } > > > > - if (list_empty(&dmar_rmrr_units)) { > > + if (list_empty(&dmar_rmrr_units)) > > printk(KERN_INFO PREFIX "No RMRR found\n"); > > - return -ENODEV; > > - } > > > > return 0; > > } > > >From your description I am unable to work out how important this fix is. > > Is it needed in 2.6.25.x? In 2.6.26? In 2.6.27? There's no way for me to > know :( Actually this is the same as Suresh' x2apic patch 05/26. The absence of RMRRs will prevent kernel from parsing IOxAPICs without this patch and thus leaves IOxAPICs in an uninitialized state.