From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Tue, 10 Oct 2006 20:40:54 +0100 (BST) Received: from 81-174-11-161.f5.ngi.it ([81.174.11.161]:39097 "EHLO mail.enneenne.com") by ftp.linux-mips.org with ESMTP id S20039922AbWJJTkw (ORCPT ); Tue, 10 Oct 2006 20:40:52 +0100 Received: from zaigor.enneenne.com ([192.168.32.1]) by mail.enneenne.com with esmtp (Exim 4.50) id 1GXMTC-0007vE-32; Tue, 10 Oct 2006 20:36:56 +0200 Received: from giometti by zaigor.enneenne.com with local (Exim 4.63) (envelope-from ) id 1GXNT2-00060O-QB; Tue, 10 Oct 2006 21:40:44 +0200 Date: Tue, 10 Oct 2006 21:40:44 +0200 From: Rodolfo Giometti To: Dan Malek Cc: linux-mips@linux-mips.org Message-ID: <20061010194044.GD14539@enneenne.com> References: <20061010182747.GA14539@enneenne.com> <29381BAC-4A96-4BFE-8E86-836A3564F2F5@embeddedalley.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <29381BAC-4A96-4BFE-8E86-836A3564F2F5@embeddedalley.com> Organization: GNU/Linux Device Drivers, Embedded Systems and Courses X-PGP-Key: gpg --keyserver keyserver.linux.it --recv-keys D25A5633 User-Agent: Mutt/1.5.13 (2006-08-11) X-SA-Exim-Connect-IP: 192.168.32.1 X-SA-Exim-Mail-From: giometti@enneenne.com Subject: Re: Problem on au1100 USB device support X-SA-Exim-Version: 4.2 (built Thu, 03 Mar 2005 10:44:12 +0100) X-SA-Exim-Scanned: Yes (on mail.enneenne.com) Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 12883 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: giometti@linux.it Precedence: bulk X-list: linux-mips On Tue, Oct 10, 2006 at 03:33:45PM -0400, Dan Malek wrote: > > Many people, including myself, have spent way too many > hours trying to make this device interface work. There > are some errata associated with it, along with some challenging > design problems. I have only been able to make it work > in one instance, with a highly custom RTLinux driver, > properly matched FIFOs and DMA, and running TCP/IP > over the link. It wasn't 100% reliable, but the TCP retries > made it appear that way to the application (with tolerable > delays). May I have your setup sequence? At least I'd like to se some bus activity... > The device interface just requires too much babysitting > by the CPU to function, and the Linux interrupts > have too much latency to guarantee the CPU can do > what is necessary in a timely fashion. The same is > true of not using DMA. If you choose not to use the > DMA for data transfer, the CPU just can't respond > quickly enough to the interface state changes > unless you just spend all of your time polling the > interface. Ok, but as first step I'd like having some functionality with FIFOs. > IMHO, I wouldn't waste much time on this, but > Good Luck if you choose to do so :-) Thanks a lot! Rodolfo -- GNU/Linux Solutions e-mail: giometti@enneenne.com Linux Device Driver giometti@gnudd.com Embedded Systems giometti@linux.it UNIX programming phone: +39 349 2432127