Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933048AbXINQOA (ORCPT ); Fri, 14 Sep 2007 12:14:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755330AbXINQNv (ORCPT ); Fri, 14 Sep 2007 12:13:51 -0400 Received: from 8bytes.org ([88.198.83.132]:53229 "EHLO 8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752859AbXINQNv (ORCPT ); Fri, 14 Sep 2007 12:13:51 -0400 Date: Fri, 14 Sep 2007 18:13:46 +0200 From: Joerg Roedel To: Manu Abraham Cc: Markus Rechberger , "linux-dvb@linuxtv.org" , "video4linux-list@redhat.com" , "akpm@linux-foundation.org" , "linux-kernel@vger.kernel.org" Subject: Re: [linux-dvb] [PATCH] Userspace tuner Message-ID: <20070914161345.GB8998@8bytes.org> References: <46E95C54.4060502@gmail.com> <46E99F36.8090809@hauppauge.com> <46E9DDC7.4000403@hauppauge.com> <46EA3F07.9050806@gmail.com> <20070914091535.GA8998@8bytes.org> <46EA77DE.8060109@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <46EA77DE.8060109@gmail.com> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2053 Lines: 45 On Fri, Sep 14, 2007 at 04:00:30PM +0400, Manu Abraham wrote: > Joerg Roedel wrote: > > On Fri, Sep 14, 2007 at 11:57:59AM +0400, Manu Abraham wrote: > >>>>> What do you think about IOMMU? > >>>>> > >>>>> > >>>> Just because AMD or INTEL want to invent some whizzy new technology it > >>>> doesn't say anything about the TV card development and retail business. > >>>> Intel and AMD have teams of Linux engineers helping operating system > >>>> developers bring their ideas and technologies to new platforms. That's a > >>>> million miles away from any of the TV board vendors I know of, who have > >>>> little or NO fulltime linux developers and consider the < 5% market > >>>> fringe at best. > >>>> > >>> it helps to virtualize devices and introduces newer features for that. > >>> Some interesting projects could be derrived out of that, there are > >>> quite a few interesting papers floating around how drivers could be > >>> handled in future. > >>> > >> IOMMU can be considered similar to the AGP GART, which is similar, > >> remapping the Addresses, as far as i understand. > > > > Common new IOMMUs have only very few in common with the AGP GART. In > > fact, with current modern IOMMU hardware it will be possible to > > implement secure userspace device drivers that are even able to do DMA. > > This is not possible with the GART. > > > >> Though you get a physical to virtual translation, what about interrupts, > > > > Modern IOMMUs are able to remap interrupts. This will solve the problem > > with PCI interrupt sharing. > > What CPU's are we talking about ? IOMMUs are not necessarily a CPU feature. These IOMMUS will be found in the South/North Bridge or even on PCI devices itself (uncommon). The Calgary IOMMU is such an example of an IOMMU not implemented on the CPU itself. Joerg - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/