From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760032Ab1FAVvo (ORCPT ); Wed, 1 Jun 2011 17:51:44 -0400 Received: from one.firstfloor.org ([213.235.205.2]:53142 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758812Ab1FAVvn (ORCPT ); Wed, 1 Jun 2011 17:51:43 -0400 Date: Wed, 1 Jun 2011 23:51:38 +0200 From: Andi Kleen To: Daniel Haid Cc: Konrad Rzeszutek Wilk , linux-kernel@vger.kernel.org, Andi Kleen , alexdeucher@gmail.com, airlied@redhat.com Subject: Re: Question about iommu on x86_64 and radeon driver. Message-ID: <20110601215138.GG27166@one.firstfloor.org> References: <20110527155507.GB11273@dumpdata.com> <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> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <21491fcfb013e21177140326efc0ee66@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 05:10:44PM +0100, Daniel Haid wrote: > >Look in the source code. I somehow assumed it would activate it > >but maybe it isn't. And the problem you have is related to > >something else? > > If I have read the code correctly the only way to get > swiotlb_force=1 in lib/swiotlb.c is to add the "swiotlb=force" > argument to the kernel parameters. > > Without it on VIA chipsets swiotlb gets activated, but with > swiotlb_force=0. In this case DMA to addresses below 4GB should be > direct. > > But since I still get the error the radeon driver must (incorrectly) > allocate memory above 4GB somewhere, but where? Someone has to debug it. grep for the error message, read the surrounding code, add printks, run it, until you figure out which allocation has the problem. Adding some radeon driver people to cc. The original problem is described in http://choon.net/forum/read.php?21,106131,115940 -Andi -- ak@linux.intel.com -- Speaking for myself only.