[Jack-Devel] Jack/USB cycle of USB output Sound device.

[Thomas Brand]

On Sat, March 30, 2019 04:45, liebrecht at grossmann-venter.com wrote:
> Question
> Is there a daemon available that monitors the usb device 1818vsl in my
> case and then reconnects if the device is unplugged and replugged ?
>

I think it's not that simple. If jack looses its backend, there's nothing
to connect to, no clock etc. Even if jack can take care of the time where
no backend is available, if a new backend is attached, it might have a
different SR or different buffersize. Clients aren't usually prepared for
that. The best a client can do is listen to server shutdown messages, wait
for the server to come back and eventually re-initialize according to new
jack SR/buffer size.

> If not, I will have to write such daemon for my own purposes and it is
> no sweat doing it, but just wondered if I am maybe missing  that someone
> already done it as it is a blatantly obvious missing piece. I ask as I
> dont want to reinvent the wheel if it already exists.

There is another missing bit, AFAIK the alsa devices don't have a unique
id, it makes it almost impossible to create fixed relationships between
devices and other logic. I don't want to say that its impossible but if it
would be easy it would possibly already exist. That said .. i saw people
ripping of the audio interface / swapping on Apple computers and the
system somehow managed to not go into strange state.

Greetings
Thomas