Hello 
I’m happy to be here, I’m starting with Rasperry Pi and DietPi.
I have a Raspberry Pi 4 8GB with a Hifiberry Dac + Adc pro.
I’ve activated realtime priority for jack server with dpkg-reconfigure jackd2 ( which had created
/etc/security/limits.d/audio.conf file with this script :
# Provided by the jackd package.
#
# Changes to this file will be preserved.
#
# If you want to enable/disable realtime permissions, run
#
# dpkg-reconfigure -p high jackd2
@audio - rtprio 90
@audio - memlock unlimited
#@audio - nice -19
By the way, when I set priority into Qjackctl GUI setting, it has no effect, I though it should be relied to @audio - rtprio 90 command? Maybe I misunderstood something? …
Realtime priority doesn’t work as we can see with this command:
The issue isroot@DietPi:/# ulimit -l -r
max locked memory (kbytes, -l) 999976
real-time priority (-r) 0
That’s because I didn’t add an audio user and I’m stuck here… 
I did:
root@DietPi:/# gpasswd -a ''root'' audio
Adding user root to group audio
I check that with:
root@DietPi:/# groups
root
But, in accordance with this tutorial : Linux MAO | PAM, I have to see audio when I type groups.
Vérifiez d’abord que votre utilisateur n’est pas déjà dans le groupe visé en émettant cette commande dans un terminal :
groups
Cette commande liste les groupes Linux dans lesquels se trouve l’utilisateur qui l’a lancée. Si audio ou jackuser n’apparaissent pas, vous n’y êtes pas !
Is precisely here I’m stuck… Realtime priority doesn’t work and I don’t understand why I haven’t audio term when I type root@DietPi:/# groups.
Please, may someone can help me with that? I’m a novice, I have some difficulties to found the issue…
Big thx in advance about your involment
PS: some informations for help if needed:
root@DietPi:/# groups audio
groups: ‘audio’: no such user
root@DietPi:/# groups root
root : root audio
root@DietPi:/# groups dietpi
dietpi : dietpi audio
root@DietPi:/# fgrep -ie 'audio' /etc/group
audio:x:29:root,dietpi
