This may affect users of other distros
I am using OpenSuse for quite some time up to version Leap 15.6 and then (with some difficulty) transferred to Leap 16.0
Leap 16.0 is using “pipewire”.
One, for Ardour users, significant change from 15.6 to 16.0 is
/etc/security/limits.d was moved to /usr/etc/security/limits.d
/etc/security still exists
That has implications to
“ How do I configure my linux system to allow JACK to use realtime scheduling? “
When adding 99-realtime.conf to /usr/etc/security/limits.d
An admin application “ Cockpit “ is not accessible.
I do not know If Cockpit is used in other distros. If yes , they may face the some problem.
So where to place 99-realtime.conf ? According to Suse forum moderator it should be placed to /etc/security/limits.d because this location is not subject to updates/upgrades
So I did !! But Cockpit was not accessible… again !! Same Problem.
I found a work-around by adding the contents of 99-realtime.conf to 25-pw-rlimits.
( /usr/etc/security/limits.d/25-pw-rlimits ). This was an educated guess on my part. 
The amended contents of 25-pw-rlimits.conf
# This file was installed by PipeWire project for its libpipewire-module-rt.so
# It is up to the distribution/user to create the @pipewire group and to add the
# relevant users to the group.
#
# PipeWire will fall back to the RTKit DBus service when the user is not able to
# acquire RT priorities with rlimits.
#
# If the group is not automatically created, the match rule will never be true
# and this file will have no effect.
#
@pipewire - rtprio 95
@pipewire - nice -19
@pipewire - memlock 4194304
#
#
# Following Mod applied 24th April 2026 Otto Hase
#
#Ardour mod
#
@audio - rtprio 99
# for rosegarden 18/9/22 and Ardour 5th Jan 2026
@audio - nice -15
@audio - memlock unlimited
#
# End of Mod
#
# End of File
#
Your thoughts/input/comments …
best regards