[alsa-devel] Alsa: USB Class 2 Audio soundcard device disappears suddenly

Joao Bonina bonina_2001 at yahoo.com
Wed Aug 1 12:07:59 CEST 2012

> From: Alan Stern <stern at rowland.harvard.edu>
>To: Joao Bonina <bonina_2001 at yahoo.com> 
>Cc: Daniel Mack <zonque at gmail.com>; "alsa-devel at alsa-project.org" <alsa-devel at alsa-project.org>; linux-usb <linux-usb at vger.kernel.org> 
>Sent: Tuesday, 31 July 2012, 15:35
>Subject: Re: [alsa-devel] Alsa: USB Class 2 Audio soundcard device disappears suddenly
>On Tue, 31 Jul 2012, Joao Bonina wrote:
>> You're right about the EMI message, it's happening when the streaming stops.
>> I've tried different cables before, but that didn't solve the problem.
>> The motherboard is an Alix 1D, and I'm using the onboard USB 2.0 ports.
>> If this really is an EMI issue, guess I'll have to source some kind of miniPCI-USB 2.0 card and see if that solves the problem.
>Another possibility is to put a USB hub before the sound device.  That 
>_might_ clean up the signal.
>Alan Stern

Thanks for that suggestion, Alan.

I  used a cheap hub that I had stashed away. At the begining that seemed to solve the problem. But after a while, some clicks and pops became audible.

Disconnected it all for a while, and when I reconnected, the problem was back again with this message on mpd.log:

Aug 01 05:57 : output: "USB" [alsa] failed to play: No such device
Aug 01 05:57 : output: closed plugin=alsa name="USB"

This time, there's no EMI message in dmesg. 

Still have to try copying files from one usb flash to another.

João Bonina


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