Re: [linux-audio-user] USB Audio + docking station/powered hub(audiotrak optopla - Linux-audio-user

2 Apr 2004

the problem appears to be that most USB hubs (like my port replicator) only 
support asynchronous transfer while audio devices need isochronous 
transfers. That would mean, most likely, that if I plugged a hub that 
supports isochronous transfer, for example the griffin hub, into my 
asynchronous docking station I would still have problems...

# lsusb -v | grep Synch

just gives numerous Synch Type none listings

so it looks like i have to ditch the docking station unless anyone else can 
think of something :(

Thanks again,
- Jonathan Beilin

...
 From: Steve Harris &lt;S.W.Harris(a)ecs.soton.ac.uk&gt;
Reply-To: A list for linux audio users 
&lt;linux-audio-user(a)music.columbia.edu&gt;
To: linux-audio-user(a)music.columbia.edu
Subject: Re: [linux-audio-user] USB Audio + docking station/powered 
hub(audiotrak optoplay)
Date: Thu, 1 Apr 2004 23:04:48 +0100

On Thu, Apr 01, 2004 at 12:36:28PM -0800, Jonathan Beilin wrote:
  Hi, I'm running gentoo on a dell inspiron
8600 with a docking station &  a
  powered USB hub. When I'm undocked with the
audiotrak optoplay plugged  in
  directly, it works fine. However, if I try to
plug the optoplay in to  the
  docking station or the wall-wart powered USB hub
the optical-digital  light
  is very faint and I get broken pipe reports when
I send a signal to the
 device. What is wrong? 
Thats interesting. This product:
http://www.griffintechnology.com/products/usbaudio_hub/ claims to be a
"USB Audio" hub, and I always thought it was BS, but maybe theres some
truth in it.

Sorry I dont have any helpful suggestions :( It could be that the audio
device is trying to draw more power from a single port than the hub or
docking station wants to provide, you can find out by running lsusb -vv as
root and looking for the MaxPower line of your audio device and the power
allowance (dunno what thats called) of the hub. The docking station will
probably be a hub too.

- Steve 
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