From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762953AbZEHJfk (ORCPT ); Fri, 8 May 2009 05:35:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755473AbZEHJf2 (ORCPT ); Fri, 8 May 2009 05:35:28 -0400 Received: from 8bytes.org ([88.198.83.132]:44518 "EHLO 8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755249AbZEHJf1 (ORCPT ); Fri, 8 May 2009 05:35:27 -0400 Date: Fri, 8 May 2009 11:35:27 +0200 From: Joerg Roedel To: David Miller Cc: dwmw2@infradead.org, airlied@linux.ie, linux-kernel@vger.kernel.org, fujita.tomonori@lab.ntt.co.jp, iommu@lists.linux-foundation.org, mingo@redhat.com Subject: Re: IOMMU and graphics cards Message-ID: <20090508093526.GB13708@8bytes.org> References: <20090507164742V.fujita.tomonori@lab.ntt.co.jp> <20090507100114.GF4059@amd.com> <1241691721.3531.73.camel@macbook.infradead.org> <20090507.113632.210373283.davem@davemloft.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090507.113632.210373283.davem@davemloft.net> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 07, 2009 at 11:36:32AM -0700, David Miller wrote: > From: David Woodhouse > Date: Thu, 07 May 2009 11:22:01 +0100 > > > On Thu, 2009-05-07 at 12:01 +0200, Joerg Roedel wrote: > >> > Looks like the DRM code uses the DMA API. > >> > >> The proprietary drivers make problems so far. For the ATI one I am in > >> contact with the developers to try to fix it. But I can't do anything > >> about the other proprietary driver I am aware of :-( > > > > I see no harm in "breaking" code which was already broken. If that's the > > only reason we're enabling the graphics workaround, let's turn it off. > > Seriously, this is an enormous price to pay just for one bad apple > proprietary driver. > > I can't believe the level of concessions some people are suggesting. This concession is already in the VT-d code. And this concession is _enabled_ in enterprise distribtions supporting VT-d. I don't like the way it is implemented there and I definitly will not implement a similar way for the AMD IOMMU. What I try to achieve is a consistent solution for both IOMMUs. Having the broken drivers work on VT-d but not on AMD IOMMU is clearly a bad solution. The other way to achieve consistency is to remove the workaround from VT-d code which significantly increases the chance to get the broken stuff fixed. David? > Let's not make IOMMU's basically useless by working around one broken > driver. Agreed. > Proper interfaces for what this driver is trying to do have existed in > the kernel for 10+ years. There are no excuses, and it's time for > Nvidia to get with the game plan. Agreed. Joerg