Weird behaviour of jackd, qjackctl and qtractor on an arm64 system

[Bruzo]

I guess this might be a very far off topic: I'm trying to get qtractor to run on a liberated ARM based chromebook running ubuntu 22.04 with xfce.

What works: starting jackd on the command line "jackd -r -d alsa" - after - starting qjackctl ( without hitting the start button! ). Then I can start qsynth and some midi program like tuxguitar, use the graph view of qjackctl to connect/disconnect the midi port to qsynth and have midi playback on/off by changing the connection in qjackctl. So the basic functionality of jack audio seems to work and even that part of qjackctl. No xrun errors even.

As soon as I hit the start button on qjackctl - even when adjusting the settings so that the command should be the jackd command that works on the command line - qjackctl just crashes with the output "aborted" on the command line. When I hit that start button qjackctl starts a jackd process before it crashes though. So I do not think the problem is in running the jack demon.

Same is true for qtractor, as it also tries to restart the jackd upon firing up - which leads to the very same crash/error message "aborted".

However the jackd I have running in a terminal outputs this when qtractor tries to communicate with it:

Cannot write socket fd = 17 err = Broken pipe
CheckRes error
Could not write notification
ClientNotify fails name = Qtractor notification = 10 val1 = 3 val2 = 0
Cannot write socket fd = 17 err = Broken pipe
CheckRes error

Which tells me that qtractor knows how to reach jackd, but for some reason jackd can't answer ... and I have no idea how to figure out what the issue might be...

Any ideas what I could try?

[rncbc]

it's probably interesting how you can hit the 'Start' button when you say you're already running jackd from the command line, or isn't it??

isn't the qjackctl main display saying 'Active' as server state ? that would tell qjackctl is running in pure jack client mode so the 'Start' button should have been disabled (grayed out)... but it seems it isn't... if it would be working on premises why do you ever want to 'Start' it on qjackctl, may I ask? my guess is that jackd is NOT working, at all.

last time I've checked tuxguitar doesn't work with jack audio--it runs on alsa directly--so that's no evidence you have jack working anyway.

please check and double check you have jackd up and running in the first place (or pipewire-jack if that's the case).

[RichardC]

I have found what seems to be very similar behaviour. I'm running an Ubuntu ARM-64 VM on an M3 Mac. Starting jack in the console works just fine and some apps can connect via jack with no problem.

However, trying to start jack from a fresh reboot using Qjackctl, (with the same jack parameters as the console start) just causes Qjackctl to crash as soon as the start button is pressed. Similarly, if I run Qtractor (again from a fresh reboot) it tries to start jack and then crashes.

The error messages are similar to the OP above.

[Linuxmusician01]

[...] I'm trying to get qtractor to run on a liberated ARM based chromebook running ubuntu 22.04 with xfce.
[...]

What method did you use to install Linux on the Chromebook? Crouton, which is a chroot? A chroot may have permission problems...

[Bruzo]

After checking and finding out that qsynth was really only using alsa output and the jackd was never involved I tried the dummy output which also caused a crash, so I figured something must be weird, went into synaptic to see what jack components were installed and it was jackd2 but some other parts were of version 1, so I replaced jackd2 with jackd1 and then I could fire everything up. Everything works as intended now, qtractor, qsynth, qjackctl, all good!

TLDR: replaced jackd2 package with jackd1 ( 2 was installed by default )

p.s.: It's not crouton, I used a bootable sd card image (from hexdump0815s github, the fennel14 image for mt8183 based systems - its an Ideapad 3) and dd'd it on the devices internal storage, there is nothing of ChromeOS left.

[Linuxmusician01]

[...]
p.s.: It's not crouton, I used a bootable sd card image (from hexdump0815s github, the fennel14 image for mt8183 based systems - its an Ideapad 3) and dd'd it on the devices internal storage, there is nothing of ChromeOS left.

[off topic] Wow! A whole new method to get Linux on a Chrombook to study for me. Do you have more tips and hints on Linux on a Chromebook? May be worth a separate topic. Chromebooks are affordable, last long on battery and are in principle compatible w/ Linux because of the kernel they use.