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

[Jonathan Beilin]

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 <S.W.Harris at ecs.soton.ac.uk>
>Reply-To: A list for linux audio users 
><linux-audio-user at music.columbia.edu>
>To: linux-audio-user at 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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