From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Clemens Ladisch" Subject: Re: C-Media / usb device bug ? Date: Tue, 19 Sep 2006 08:36:43 +0200 Message-ID: <1158647803.13410.271265867@webmail.messagingengine.com> References: <200609181921.10510.pyaggi@alsurdelsur.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <200609181921.10510.pyaggi@alsurdelsur.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: alsa-devel-bounces@lists.sourceforge.net Errors-To: alsa-devel-bounces@lists.sourceforge.net To: Pablo Yaggi , alsa-devel@lists.sourceforge.net List-Id: alsa-devel@alsa-project.org Pablo Yaggi wrote: > I'm working in a multi-capture application with alsa and i discovered > if i attach two "c-media usb headphone set" adapters to an usb hub which > is attached to my computer when i try to read from the two devices the > first one read (also open) errors with (-77) bad file descriptor status > and the other one keep working. When i attach the two devices directly to > the usb connectors (without hub) all works fine, the two devices can be > read at the same time. What kernel version are you using? The EHCI transaction translator code (which is responsible for moving audio data through an high speed hub) got a bugfix in 2.6.17, but still artificially limits the bandwidth. It will be rewritten in 2.6.18. HTH Clemens ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys -- and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV