From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751063AbWGDEB5 (ORCPT ); Tue, 4 Jul 2006 00:01:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751158AbWGDEB5 (ORCPT ); Tue, 4 Jul 2006 00:01:57 -0400 Received: from mail.suse.de ([195.135.220.2]:24999 "EHLO mx1.suse.de") by vger.kernel.org with ESMTP id S1751063AbWGDEB4 (ORCPT ); Tue, 4 Jul 2006 00:01:56 -0400 Date: Mon, 3 Jul 2006 20:58:22 -0700 From: Greg KH To: Daniel Bonekeeper Cc: Alon Bar-Lev , kernelnewbies@nl.linux.org, linux-kernel@vger.kernel.org Subject: Re: Driver for Microsoft USB Fingerprint Reader Message-ID: <20060704035822.GA18865@kroah.com> References: <9e0cf0bf0607030304n62991dafk19f09e41d69e9ab0@mail.gmail.com> <44A95F12.8080208@gmail.com> <20060703214509.GA5629@kroah.com> <20060703222645.GA22855@kroah.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 03, 2006 at 11:56:26PM -0400, Daniel Bonekeeper wrote: > Maybe this is not a default on the market and is something that is > coming... but seems that some USB controllers are coming with DMA > capabilities: > > http://www.usb.org/developers/presentations/pres0501/Augustin_DMA_Implem_Final.ppt > http://www.semiconductors.philips.com/pip/isp1183.html I think you are a bit confused. Of course the USB Host controller devices support DMA, that's how things are set up and work properly without using a ton of CPU. They are usually PCI devices and work quite well and use DMA. It's the USB devices themselves that don't and can't do any DMA themselves. Hope this helps explain things. greg k-h