From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Steven J. Ackerman" Subject: RE: Linux USB Serial Date: Mon, 17 Sep 2012 18:27:40 -0400 Message-ID: <00c501cd9523$a68524f0$f38f6ed0$@acscontrol.com> References: <00a301cd950a$ae9081d0$0bb18570$@acscontrol.com> <87zk4o1kh4.fsf@nemi.mork.no> <00b801cd9518$715dd160$54197420$@acscontrol.com> <20120917214136.GA20773@kroah.com> <00c101cd951f$55626910$00273b30$@acscontrol.com> <20120917220813.GA7780@kroah.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from gwa3.webcontrolcenter.com ([63.134.207.12]:33640 "EHLO gwa3.webcontrolcenter.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757338Ab2IQW2a (ORCPT ); Mon, 17 Sep 2012 18:28:30 -0400 In-Reply-To: <20120917220813.GA7780@kroah.com> Content-language: en-us Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: 'Greg KH' Cc: =?iso-8859-1?Q?'Bj=F8rn_Mork'?= , linux-usb@vger.kernel.org, linux-serial@vger.kernel.org > That's fine, the cdc-acm interface will work for that. > > But is your device really a CDC ACM device? Or is it something else? The device is a 3.5" color LCD display with touchscreen that can act as a serial terminal. It just needs to be able to send and receive characters over an USB serial port. > You wouldn't, if you use the ftdi serial chip in your device. Which > begs me to ask, what type of usb to serial chip is in your device? What > protocol does it use to talk to the host? The device is based upon a Renesas RX62N processor which has a USB interface in it. The protocol is supposedly based upon the CDC - a control endpoint and two bulk endpoints. The software was derived from a demo supplied by the manufacturer - and it does work under Windows. The device enumerates as a COM port and you can interact with the display using a program or a terminal emulator. Unfortunately the chip vendor doesn't have any support for Linux. > They shouldn't have to do that, once we get it working, they get the > update automatically from their distro. But if you can't test any > changes we make to try to get this to work, there's not much we can do > here, right? > I guess that I'm operating under the assumption that there is something wrong on my end - an incorrectly configured descriptor for example. It appears the other USB serial devices work OK under Linux - even without custom drivers. I'm hoping that I can find an error message somewhere that will tell me what I'm doing wrong - or that somebody who has been down that path before can't point to something obvious - like Bjrn did. > Oh, and fix that descriptor up in your firmware, that might solve > everything :) Going through the USB CDC documentation between e-mails. Other than the incorrect bInterfaceSubClass value - which I have corrected - nothing else seems wrong. > > Hope this helps, > > greg k-h Always appreciate your assistance - thank you! Steven J. Ackerman, Consultant ACS, Sarasota, FL http://www.acscontrol.com mailto:steve@acscontrol.com