9 Feb
2025
9 Feb
'25
6:08 p.m.
Hi,
Long-time lurker, first time posting ...
On 2/9/25 10:38 AM, Len Ovens wrote:
On Sun, 9 Feb 2025, Peter P. wrote:
I use JACK in the (US) broadcast industry, mostly with Rivendell radio
automation (https://rivendellaudio.org/).
After being frustrated at the "hot plug" nature of USB and the lack of
it with JACK I came up with a (pretty kludgy) workaround: using udev
rules and a simple shell script to add and remove jack clients from the
graph.
With a rule like the one below for example (watch the wrap):
# Focusrite Scarlett 4i4: 1235:8212
ACTION=="add", ATTR{idVendor}=="1235",
ATTR{idProduct}=="8212",
ENV{JACK_PROMISCUOUS_SERVER}="audio",
RUN+="/usr/local/bin/jack-reconnect -v -v USB Scarlett4i4-1"
and the ZSH script at
https://github.com/opensourceradio/ram/blob/master/usr/local/bin/jack-recon…
one can "automatically" have one's Scarlett 4i4 (with USB ID 1235:8212)
connect and be inserted into the jack graph each time it is plugged in.
In case it's not obvious, this works only on Linux with a working udev
installation.
~David Klann
I am running an Edirol UA-25 audio interface under jackd2. When I
disconnect the device with jackd running, it will print
A long time ago, when jackd was designed, there were audio interfaces that
would fit in one of the mother board slots. They were called ISA slots.
These audio cards could only be removed when the beast was powered down.
Jackd is a manually set up utility, it is told the device name at start
and as such, it has no idea what to do when that device vanishes. It is
possible with the tools supplied to tell jack to change it's device or
backend while running via dbus. I have had varying amounts of success
doing this after the USB device has been pulled. I would guess that
because it is possible to change the device like this, jackdbus continues
to run in hopes something else will happen.
Basically, a device vanishing in an audio context is a system failure. USB
might be designed for hot plugging but jackd is not.
--
Len Ovens
www.ovenwerks.net
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