From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Wagner Subject: Driver(s) for IEEE 1394 based break out boxes Date: Mon, 12 Jul 2004 21:19:30 +0200 Sender: alsa-devel-admin@lists.sourceforge.net Message-ID: <20040712191930.GA20382@vis.ethz.ch> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail.vis.ethz.ch (naboo.ethz.ch [129.132.17.66]) by alsa.alsa-project.org (ALSA's E-mail Delivery System) with ESMTP id 200C5266 for ; Mon, 12 Jul 2004 21:19:32 +0200 (MEST) Received: from selonia.vis.ethz.ch (selonia.vis.ethz.ch [192.168.2.2]) by mail.vis.ethz.ch (Postfix) with ESMTP id E5823741F8 for ; Mon, 12 Jul 2004 21:19:30 +0200 (CEST) Received: from wagi by selonia.vis.ethz.ch with local (Exim 3.35 #1 (Debian)) id 1Bk6Ko-0005In-00 for ; Mon, 12 Jul 2004 21:19:30 +0200 Content-Disposition: inline Errors-To: alsa-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: alsa-devel@alsa-project.org List-Id: alsa-devel@alsa-project.org Hi, There're several IEEE 1394 based break out boxes on the market for which no drivers exist for Linux [1] (The web site has a translation to english, but the content seems to disappear, at least for the IEEE 1394 boxes.) . The interesting fact about those boxes is that all but one are using the same chip (dm1000). Furthermore, the communication protocol(s) between break out box and computer is documented and "public" available. Yes, you have to be member of those groups to read the documents but in the general idea it's available. Relevant standards are: IEC 61883 1394ta AVC 1394ta Audio and Music Data Transmission Protocol I'm still trying to figure out what's the best way to write a driver. On the on hand, there exists already the IEEE 1394 stack with IEC 61883 support in user-land. I don't know if the libiec61883 is already ready to use but still it exists. As I understand the general idea behind libraw1394 and libiec61883 is to do as much as possible in users-pace. Any application which wants to take advantage of IEEE 1394 based sound cards has to use those libraries. I guess it means for jack to have a new backend in order to use those cards. But most application wont be aware of this interface, I suppose. On the other hand ALSA provides a well known interface which most sound based application are using. To write a new driver for a sound card, you end up writing an ALSA kernel driver because libasound is not designed to use other interfaces than the ALSA kernel interface (this is an assumption). So it is not possible to use libraw1394 and libiec61883. A new kernel driver has to be written with implements those parts. Of course it needs some more things but I'm just writing my lousy ordered thoughts down. The question is which way to go? Get the break out boxes working with the existing libraries or write an ALSA driver which implements those parts again? Personaly, I think ALSA might be the better idea but it does not make use of the already written code. Maybe there exists a better way... thanks, daniel [1] http://www.soundkartenkatalog.de/deu2/pi-1117011340.htm?categoryId=28 ------------------------------------------------------- This SF.Net email sponsored by Black Hat Briefings & Training. Attend Black Hat Briefings & Training, Las Vegas July 24-29 - digital self defense, top technical experts, no vendor pitches, unmatched networking opportunities. Visit www.blackhat.com