[LAD] jackd and usb hub

Luis Garrido luisgarrido at users.sourceforge.net
Wed Oct 13 18:01:02 UTC 2010

On Wed, Oct 13, 2010 at 2:02 PM, Robin Gareus <robin at gareus.org> wrote:
> With the USB2 hub I also get
> ALSA urb.c:856: cannot submit datapipe for urb 0, error -28: not enough
> bandwidth
> ALSA midi.c:214: urb status -32
> messages and jackd won't start.

Does the hub cause this problem also through a regular USB port (not PCMCIA)?

> but connecting the UA-25 directly to the PCMCIA/USB2 card works if I
> also connect some external power supply to the PCMCIA card. Did you try
> that?

Believe it or not, that combination hadn't crossed my mind yet: using
the brand new shiny and otherwise useless hub as a 16 € glorified 5V
regulator between its power supply and the PCMCIA card. Why the heck
not, eh? One fewer layer, too.

Well, there's my workaround, thanks Mr. Gareus! But (it couldn't have
been that easy, could it?) only works on one of the two USB/PCMCIA
ports. Trying to use the other one gets me this nice message:

ALSA sound/usb/usbaudio.c:1348: 40:1:1: usb_set_interface failed


Anyone interested in a moderately used Edirol UA-25 interface with
some occasional -74 dB noise at 13.1 kHz, and a penchant for serial
(bus) killing?

Anyway, I think this hub issue is worth looking into. Old USB 1.1 hubs
don't mess with realtime audio and new USB 2.0 do? Now that's not
exactly what I'd call an improvement. What can we expect from USB 3.0?



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