LMMS 未在运行 Ubuntu 21.04 的树莓派 4b 上启动

两三天前就开始了。我在树莓派 4b 上安装了 ubuntu 21.04，并在其上安装了 lmms。它工作得很好，但是有一天，我尝试从 pulseaudio 切换到 jackd2 作为音频服务器。我把延迟降到最低。（我会显示一个屏幕截图，但 lmms gui 不起作用。）它显示启动屏幕，但现在它不会显示 gui。有时会弹出一个错误窗口，说“ubuntu 有内部错误”，另一个说“lmms 意外关闭”。每次我尝试时它都不会这样做；有时它什么也没有显示。它只是没有调出gui。我尝试通过终端启动 lmms，这些是它产生的错误日志。

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():  

我以几种不同的方式重新安装了 lmms，例如通过终端使用 snap、通过 snap sotre 进行 snap 以及通过 apt 终端进行 snap，但它也有同样的问题。知道可以做些什么来修复它吗？似乎与错误安装的千斤顶有关。我尝试重新安装我能找到的所有 jack、libjack 和 jackd 软件包，但还没有修复。