[ubuntu-studio-users] jack not starting at boot if Zoom L-12 is on

[Alan W. Kerr]

OK, I've reinstalled 18.04 (with the backports).
All seems good except for one strange behavior...

I have a Zoom L-12 which is a USB 14 in/4 out, class-compliant, 
mixer/recorder/audio interface.  If the L-12 is on at boot, jack does 
not start.  I can go into Ubuntu Studio Controls and "Restart Jack", 
then have Patchage "connect to Jack", and everything is normal again.

I've tested this with only USB hardware synths on: normal, MIDI doesn't 
trigger this.
I've tested this with only a USB mike plugged-in (bus powered, so it's 
not really "on"): normal, so it's not "all USB audio".
It's just when the L-12 is on at boot...  if the L-12 is off at boot, it 
can be turned on and everything is normal.

So, the obvious "answer" is "then don't boot with the L-12 on" but 
that's not a satisfying answer...

What might be causing this?
Has anyone else had a device "block" jack from starting?
Is this some sort of "out of order booting" that only happens when the 
L-12 is on?

Thanks for any help/suggestions...


Alan W. Kerr          awkerr at aoc.nrao.edu          Whee!(tm)