[LAU] Repeated USB error/warning notification

Jeanette C. julien at mail.upb.de
Tue May 22 20:05:06 CEST 2018

May 22 2018, Chris Caudle has written:
> Is this only during startup?
Hi Chris,
thanks for the support. No, this is in normal runtime. It sometimes
happens when I just connect two devices (one or both being USB MIDI) via
aconnect. I have a FEELING that it happens more often with ALSA
sequencer ports that only exist during a specific task and are not
connectable through aconnect. My MIDI sequencer Midish has such ports.
There are a few others that ask the user to choose the destination port
in advance and only connect to it.

I have also seen it, using a program of my own that uses the RtMidi
library for MIDI I/O.

When I am in such a state, the messages are repeated as long as the
connection exists and they will show on the current terminal, which ever
that is, even including TTY switching while the messages are coming.

Yes, I think the numbers in brackets are just kernel timestamps.

I wonder: could it be that the USB hub can't transmit/receive data fast
enough? It has a USB typing keyboard and a Braille display connected,
which take energy from it and the MIDI keyboard, which is externally

Best wishes and thanks again,


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