Re: [LAU] ESI Romio II and alsa-midi-latency-test failure

On Mon, 27 Jan 2014 10:05:20 +0100, Andre Majorel wrote
> On 2014-01-26 22:55 +0100, Andre Majorel wrote:
> [...]
> > Tried the Romio II with itself again : it failed as before.
> >
> > Found a large number of "usb_submit_urb: -22" messages in
> > kern.log for yesterday (but none for today).
>
> If the Romio II is connected directly to the computer, instead
> of through a USB hub at the end of a 5-m cable,

Is that a USB-1 or a USB-2 device? 5 meters are way above
the USB-1 Specs (3m max.).

> alsa-midi-latency-test -o 24:0 -i 24:1
>
> works fine.
>
> What are you supposed to do in a case like this ? Get a better
> hub ? Get a better MIDI interface ? Work around the problem in
> software ? What a mess !

There are some devices that refuse to work with a hub (no matter
how short the cable is). My -m-Audio Axiom 61 refuses to connect
via a hub - a fact mentioned in the fine manual but _not_ in any
promotional material :-(

I think this is either a bug in their Usb chip firmware or some
engineer tried to be oversmart (i.e. hubs might introduce latency/jitter
hence we won't work with hubs).

 HTH Ralf Mattes

> It is a 7-port powered USB hub (Heden HUBUSB7PCB / HUBUSB7PCW).
>
> --
> André Majorel http://www.teaser.fr/~amajorel/
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--
R. Mattes -
Hochschule fuer Musik Freiburg
rm@email-addr-hidden-freiburg.de
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