From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757672Ab1FAWW3 (ORCPT ); Wed, 1 Jun 2011 18:22:29 -0400 Received: from one.firstfloor.org ([213.235.205.2]:39442 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753392Ab1FAWW1 (ORCPT ); Wed, 1 Jun 2011 18:22:27 -0400 Date: Thu, 2 Jun 2011 00:22:26 +0200 From: Andi Kleen To: Daniel Haid Cc: linux-kernel@vger.kernel.org, Konrad Rzeszutek Wilk , Andi Kleen , airlied@linux.ie, alexdeucher@gmail.com Subject: Re: Question about iommu on x86_64 and radeon driver. Message-ID: <20110601222226.GH27166@one.firstfloor.org> References: <9e26ea71798d10a3f900c777b71ff485@admin.gogi.tv> <20110531134519.GC14641@dumpdata.com> <59be1730ec1660abeb7b4dc584510d34@admin.gogi.tv> <20110531160221.GA31659@dumpdata.com> <0a8cb4bcad7fcf091a6bbe158323bba0@admin.gogi.tv> <20110531190412.GA21245@dumpdata.com> <20110601132444.GA4081@dumpdata.com> <21491fcfb013e21177140326efc0ee66@admin.gogi.tv> <34fa3fe7780241e452b268fd5ecfdee9@admin.gogi.tv> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <34fa3fe7780241e452b268fd5ecfdee9@admin.gogi.tv> User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 01, 2011 at 10:58:08PM +0100, Daniel Haid wrote: > I have also found out the following. In > > line 741 of drivers/gpu/drm/radeon/radeon_device.c > > there is a comment "PCIE - can handle 40-bits." - > I have a PCIE card - and then need_dma32 is not set. > > So if I read it correctly the ttm allocation > routines will allocate memory over 4GB. > > But if PCIE can handle 40 bits, why does swiotlb > give out a bounce buffer to the radeon driver at all? swiotlb only does what the driver tells it Also new drivers default to 4GB, so if a driver wants something else it has to set it explicitely. Also BTW the driver should work in any case, so likely something else is wrong. Really you need to discuss this with the radeon driver people. Readded cc. -Andi -- ak@linux.intel.com -- Speaking for myself only.