[BRLTTY] Speech output fails after an external USB keyboard is plugged in

[Eric Scheibler]

Hello,

currently I encounter a serious bug with Brltty 5.3.1 under Debian testing (stretch). When I plug
the cherry evolution stream XT USB keyboard into my laptop, speech output of espeak stops working
after some seconds (sometimes minutes). Braille output is still working fine. To fix the speech
output, I have to restart Brltty completely. If I only reload the speech driver, Brltty crashes and
the keyboard stops working too. Unfortunately this behavior persists even after I've unplugged the
USB keyboard and use the laptop keyboard again. Notebook restart also doesn't fix it.  After that, I
tested the keyboard on another PC with the same result.

How can I help to solve that issue? Which debug data do you need?

Thanks in advance
Cheers
Eric