From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753898AbYITXlx (ORCPT ); Sat, 20 Sep 2008 19:41:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751665AbYITXlp (ORCPT ); Sat, 20 Sep 2008 19:41:45 -0400 Received: from web37502.mail.mud.yahoo.com ([209.191.91.149]:27941 "HELO web37502.mail.mud.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751539AbYITXlo convert rfc822-to-8bit (ORCPT ); Sat, 20 Sep 2008 19:41:44 -0400 X-Greylist: delayed 400 seconds by postgrey-1.27 at vger.kernel.org; Sat, 20 Sep 2008 19:41:44 EDT DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=X-YMail-OSG:Received:X-Mailer:Date:From:Reply-To:Subject:To:MIME-Version:Content-Type:Content-Transfer-Encoding:Message-ID; b=sma1lWx+X8Aka3Yt5nzh9GUKUzOEqXlAQjqzsTDbTiSN4tmDa/oMzRcHT28sjCSZqHE7LjA9MmO+PZyySnlHb8VDgRl71OMQEgidkV2Exsk+BDsFwZcOJrf29G0ysETGvTXdJThRs4aXD2/ex00KzKJHXJ+S09XL8k/yQR70C2g=; X-YMail-OSG: xooi.EEVM1nSL5ycRbyiAt_9blLJ1Yp1KW4MnNajdr.mDCQ1IKX8POncP6GeYWUnjapQgQAls9acRdsqmCwhxTxcoplJLSpgkShZj2vjPwuEvjF8DDSvA4QUqdaAEJIAqViWmSiEaJYuXgECmZ33uTAV4oOSBA-- X-Mailer: YahooMailWebService/0.7.218.2 Date: Sat, 20 Sep 2008 16:35:03 -0700 (PDT) From: =?iso-8859-1?Q?cihan_=F6zt=FCrk?= Reply-To: cihanozturk@yahoo.com Subject: USB driver problem with external hub To: linux-kernel@vger.kernel.org MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Message-ID: <684433.70774.qm@web37502.mail.mud.yahoo.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I am working on a device driver for providing connectivity to a Silabs F340 board through USB. All the required software, including firmware on the device side, USB device driver and user level libraries as well as the application, are implemented. The system operates fine when experimental communication is considered, in which dummy data is simply sent and received betweeen the host and the device at Full speed. The trouble comes when a USB external hub is used as a gateway between the device and the host instead of directly connecting the USB cable from device to the USB port of the PC. The kernel log states that the transfer of urb failed due to -EPROTO(-71), which is defined as protocol error. I found in some resources that this error can be a result of (a) bitstuff error, or (b) no response packet received within the prescribed bus turn-around time, or (c)hardware problems such as bad devices (including firmware) or cables. The hub is a Digitus product with 7 ports and works fine with other USB devices such as the mouse on the same platform. My kernel version is 2.6.18. Has anyone got any idea on what can be the reason of this failure, and how can I resolve the problem? I can surely provide any additional information about the situation if any one is interested in helping out. Thanks... -------------- Cihan Ozturk