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

On 2014-01-26 22:55 +0100, Andre Majorel wrote:
> On 2014-01-26 14:56 +0100, Clemens Ladisch wrote:
>
> > What happens if you try two loopbacks at the same time, from the
> > Romio to another device, and from another device to the Romio?
>
> Tried three combinations of one alsa-midi-latency-test process
> writing to one Romio II port and another reading from another
> Romio II port :
>
> alsa-midi-latency-test -o 24:0 -i 28:7 &
> alsa-midi-latency-test -o 28:7 -i 24:0
>
> alsa-midi-latency-test -o 24:0 -i 28:7 &
> alsa-midi-latency-test -o 28:7 -i 24:1
>
> alsa-midi-latency-test -o 24:1 -i 28:7 &
> alsa-midi-latency-test -o 28:7 -i 24:1
>
> They all worked without a hitch.
>
> 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,

  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 !

It is a 7-port powered USB hub (Heden HUBUSB7PCB / HUBUSB7PCW).

-- 
André Majorel http://www.teaser.fr/~amajorel/
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