LMMS не запускается на raspberry pi 4b под управлением Ubuntu 21.04

Это началось два или три дня назад. Я установил ubuntu 21.04 на свой raspberry pi 4b и установил на него lmms. Это работало достаточно хорошо, но однажды я попытался переключиться с pulseaudio на jackd2 в качестве аудиосервера. Я уменьшил задержку до минимально возможной. (Я бы показал скриншот, но графический интерфейс lmms не работает.) Он показывает экран запуска, но теперь он не показывает графический интерфейс. Иногда появляется окно с ошибкой, в котором говорится, что «ubuntu имеет внутреннюю ошибку», а в другом — «lmms неожиданно закрылась». Это происходит не каждый раз, когда я пытаюсь; иногда вообще ничего не показывает. Он просто не вызывает графический интерфейс. Я попытался запустить lmms через терминал, и это журналы ошибок, которые он создал.

      pi@pi-raspberrypi:~$ lmms
Warning: Ignoring XDG_SESSION_TYPE=wayland on Gnome. Use QT_QPA_PLATFORM=wayland to run on Wayland anyway.
Notice: could not set realtime priority.
Cannot connect to server socket err = Connection refused
Cannot connect to server request channel
jackdmp 1.9.17
Copyright 2001-2005 Paul Davis and others.
Copyright 2004-2016 Grame.
Copyright 2016-2021 Filipe Coelho.
jackdmp comes with ABSOLUTELY NO WARRANTY
This is free software, and you are welcome to redistribute it
under certain conditions; see the file COPYING for details
JACK server starting in realtime mode with priority 10
self-connect-mode is "Don't restrict self connect requests"
audio_reservation_init
Acquire audio card Audio0
creating alsa driver ... hw:0|hw:0|1024|2|48000|0|0|nomon|swmeter|-|32bit
ALSA: Cannot open PCM device alsa_pcm for capture. Falling back to playback-only mode
configuring for 48000Hz, period = 1024 frames (21.3 ms), buffer = 2 periods
ALSA: final selected sample format for playback: 16bit little-endian
ALSA: use 2 periods for playback
Cannot use real-time scheduling (RR/10) (1: Operation not permitted)
AcquireSelfRealTime error
Cannot use real-time scheduling (RR/5) (1: Operation not permitted)
JackClient::AcquireSelfRealTime error
JackEngine::XRun: client = lmms was not finished, state = Running
JackAudioDriver::ProcessGraphAsyncMaster: Process error
JackEngine::XRun: client = lmms was not finished, state = Triggered
JackAudioDriver::ProcessGraphAsyncMaster: Process error
JackEngine::XRun: client = lmms was not finished, state = Triggered
JackAudioDriver::ProcessGraphAsyncMaster: Process error
JackEngine::XRun: client = lmms was not finished, state = Triggered
JackAudioDriver::ProcessGraphAsyncMaster: Process error
JackEngine::XRun: client = lmms was not finished, state = Triggered
JackAudioDriver::ProcessGraphAsyncMaster: Process error
JackEngine::XRun: client = lmms was not finished, state = Triggered
JackAudioDriver::ProcessGraphAsyncMaster: Process error
JackEngine::XRun: client = lmms was not finished, state = Triggered
JackAudioDriver::ProcessGraphAsyncMaster: Process error
JackEngine::XRun: client = lmms was not finished, state = Triggered
JackAudioDriver::ProcessGraphAsyncMaster: Process error
JackEngine::XRun: client = lmms was not finished, state = Triggered
JackAudioDriver::ProcessGraphAsyncMaster: Process error
JackEngine::XRun: client = lmms was not finished, state = Triggered
JackAudioDriver::ProcessGraphAsyncMaster: Process error
JackEngine::XRun: client = lmms was not finished, state = Triggered
JackAudioDriver::ProcessGraphAsyncMaster: Process error
JackEngine::XRun: client = lmms was not finished, state = Triggered
JackAudioDriver::ProcessGraphAsyncMaster: Process error
JackEngine::XRun: client = lmms was not finished, state = Triggered
JackAudioDriver::ProcessGraphAsyncMaster: Process error
JackEngine::XRun: client = lmms was not finished, state = Triggered
JackAudioDriver::ProcessGraphAsyncMaster: Process error
JackEngine::XRun: client = lmms was not finished, state = Triggered
JackAudioDriver::ProcessGraphAsyncMaster: Process error
JackEngine::XRun: client = lmms was not finished, state = Triggered
JackAudioDriver::ProcessGraphAsyncMaster: Process error
JackEngine::XRun: client = lmms was not finished, state = Triggered
JackAudioDriver::ProcessGraphAsyncMaster: Process error
JackEngine::XRun: client = lmms was not finished, state = Triggered
JackAudioDriver::ProcessGraphAsyncMaster: Process error
Destination port in attempted (dis)connection of system:playback_2 and  is not an input port
Segmentation fault (core dumped)
pi@pi-raspberrypi:~$ Destination port in attempted (dis)connection of system:playback_2 and  is not an input port
JackGraphManager::Disconnect: port_src = 10 not used name = 
Input port index = 10 not found for application ref = 2
Unknown error...
terminate called after throwing an instance of 'Jack::JackTemporaryException'
  what():  

Я переустановил lmms несколькими разными способами, например, с помощью snap через терминал, snap через snap sotre и snap через терминал apt, и у него та же проблема. Знаете, что можно сделать, чтобы это исправить? Похоже, это как-то связано с неправильно установленным домкратом. Я попытался переустановить все пакеты jack, libjack и jackd, которые смог найти, но пока не нашел исправления.