Ardour 6.7 cannot connect to JACK anymore

I just installed Ardour 6.7 and cannot connect to my JACK. Latest MIxbus and Reaper can.

I am in groups audio and realtime. I can use realtime jackd with Guitarix and Mixbus.

My Log:

Here are the errors associated with this failed session:
Log Messages:
ERROR: JACK: Cannot use real-time scheduling (RR/5) (1: Operation not permitted)
ERROR: JACK: JackClient::AcquireSelfRealTime error
WARNING: LADSPA: cannot load module “/usr/lib/ladspa/ladspa_guitarix.so” (/usr/lib> /ladspa/ladspa_guitarix.so: undefined symbol: _ZN4Glib10Dispatcher7connectEON4sigc4slotIvNS1_3nilES3_S3_S3_S3_S3_S3_EE)
WARNING: LADSPA: cannot load module “/usr/lib/ladspa/ladspa_guitarix.so” (/usr/lib/ladspa/ladspa_guitarix.so: undefined symbol: _ZN4Glib10Dispatcher7connectEON4sigc4slotIvNS1_3nilES3_S3_S3_S3_S3_S3_EE)
WARNING: Unsupported required LV2 feature: ‘LV2 Buf Size’ in ‘KlangFalter’.
WARNING: Unsupported required LV2 feature: ‘LV2 Buf Size’ in ‘Vex’.
INFO: harvid version: 803
INFO: Loading menus from /opt/Ardour-6.7.0/etc/ardour.menus
ERROR: JACK: Cannot create thread res = 1

Is this associated with Ardour 6.7?

I use Ardour with JACK all day every day. There has been no change in Ardour’s JACK support.

On the other, your system JACK config is clearly broken:

ERROR: JACK: Cannot use real-time scheduling (RR/5) (1: Operation not permitted)
ERROR: JACK: JackClient::AcquireSelfRealTime error

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I’ve ran into this before with JACK, but specifically only when I also have pipewire installed and am not using pipewire-jack. Can you give us some more details about what system and configuration you are running?

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Ardour can only use JACK if jack runs with realtime permissions.

On debian based systems, run

sudo dpkg-reconfigure -p high jackd2

and allow realtime process priority. Then re-login and configure jackd to use rt-permissions (it’s usually enabled by default if available).

Generic instructions for other distros can be found in the jack FAQ: How do I configure my linux system to allow JACK to use realtime scheduling? | JACK Audio Connection Kit

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Yes, I fixed it. It was the audio group conf. :no_mouth:

It’s a Manjaro. I already fixed it, but thanks for your help anyways. :slight_smile:

I feel a little bit dumb now. I checked the audio.conf – somehow it was not there, but in a different folder.
I really dont know, how this happened. And, how it worked all the time before installing A6.7. o.O

thanks for the awesome information.

I’ve got the same problem:

Could not create session in “/home/djnotes/ardour/mytrack”

—ERROR: JACK: Cannot create thread res = 1
ERROR: JACK: JackClient::AcquireSelfRealTime error
ERROR: JACK: Cannot use real-time scheduling (RR/15) (1: Operation not permitted)

And it does not solve after adding my user to audio and jack-user group and logging out. Any ideas?
OS: Fedora 33, Ardour upgraded by system from 5 to 6.9.0.

The answer is in a link given above, but I’ll include it again:

https://jackaudio.org/faq/linux_rt_config.html

Fedora can be a bit peculiar

see also Hello and [WARNING]: AlsaAudioBackend: cannot acquire realtime permissions. (given up on jack) - #13 by Learn_Digital_Audio

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Thanks @x42 . Thanks @paul. Following Jack documentation linked by Paul, I added my current user to jackuser and audio groups that had been added before on my system. Logged out and logged in, but the issue was not solved. However, rebooting the computer did. Seems like simply logging out and re-logging does not work on all systems.
The reason for this problem was I used to work with Ardour 5 with another user (for which I had configured JACK), and I forgot to configure JACK settings when switching to a new user, and then I didn’t work with Ardour for a long time, and suddenly this came up and I wrongly assumed it was an Ardour6 issue.