From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752238AbZHCGud (ORCPT ); Mon, 3 Aug 2009 02:50:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751927AbZHCGud (ORCPT ); Mon, 3 Aug 2009 02:50:33 -0400 Received: from mga05.intel.com ([192.55.52.89]:12106 "EHLO fmsmga101.fm.intel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751881AbZHCGuc (ORCPT ); Mon, 3 Aug 2009 02:50:32 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.43,312,1246863600"; d="asc'?scan'208";a="713357126" Date: Mon, 3 Aug 2009 14:50:30 +0800 From: Zhenyu Wang To: David Woodhouse Cc: Dave Airlie , Keir Fraser , "xen-devel@lists.xensource.com" , "linux-kernel@vger.kernel.org" , "iommu@lists.linux-foundation.org" , Joerg Roedel Subject: Re: [RFC] Make AGP work with IOMMU Message-ID: <20090803065030.GA32461@zhen-devel.sh.intel.com> Reply-To: Zhenyu Wang Mail-Followup-To: David Woodhouse , Dave Airlie , Keir Fraser , "xen-devel@lists.xensource.com" , "linux-kernel@vger.kernel.org" , "iommu@lists.linux-foundation.org" , Joerg Roedel References: <1248707041.6100.35.camel@macbook.infradead.org> <21d7e9970907282328l4a44b9a2of4500c5c84a3586b@mail.gmail.com> <1248851712.19733.214.camel@macbook.infradead.org> <21d7e9970907290143q6778511cvda1c6b915f61654a@mail.gmail.com> <1248860205.19733.238.camel@macbook.infradead.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="0OAP2g/MAC+5xKAE" Content-Disposition: inline In-Reply-To: <1248860205.19733.238.camel@macbook.infradead.org> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --0OAP2g/MAC+5xKAE Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2009.07.29 17:36:45 +0800, David Woodhouse wrote: > On Wed, 2009-07-29 at 18:43 +1000, Dave Airlie wrote: > > >> don't suppose we want page_to_gart or is the double function nicer? > > > > > > I pondered that briefly. But then observed that phys_to_gart() and > > > gart_to_phys() _always_ describe an identity mapping, so perhaps they > > > could just be ditched completely? > >=20 > > Yeah that could work too, no idea why they were introduced, well before= my time. >=20 > http://git.infradead.org/users/dwmw2/iommu-agp.git?a=3Dcommitdiff;h=3D8bf= 2f3a9 >=20 > It was introduced by Keir in 2005 for Xen (commit 07eee78e). I suspect > it can die though, and that the right answer there is also to use the > DMA API correctly. >=20 The commits on that tree looks fine to me. Thanks David!=20 I've also done some testing on G45 here, I've also seen the write faults before graphics device init or after dma unmap pages. I tried to look it up in my memo, which turns out one message like this should be a BIOS bug that doesn't initialize the GTT table correctly. But I'm quite sure about it now, better to ask our chipset people to verify if this problem has been fixed or not. --=20 Open Source Technology Center, Intel ltd. $gpg --keyserver wwwkeys.pgp.net --recv-keys 4D781827 --0OAP2g/MAC+5xKAE Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) iEYEARECAAYFAkp2iLYACgkQsQQaM014GCeUewCcCGr55DTdWt5SBQgkx4VRpLWk 5pYAn1Cs4Lw6secCjNW1eWJ3T4o5XUMk =H5CO -----END PGP SIGNATURE----- --0OAP2g/MAC+5xKAE--