如果 Ubuntu 21.04 在插入 USB 麦克风的情况下运行，pulseaudio 无法启动。但是，如果 Ubuntu 21.04 在没有 USB 的情况下运行，pulseaudio 可以正常启动，并且即使系统启动后插入 USB，它仍然可以正常工作。
当 pulseaudio 启动失败时来自 journalctl 的日志消息：
-- Boot 37de7028dfda47569d03504658160650 --
Dec 11 04:46:09 hirsute-server systemd[1958]: Starting Sound Service...
Dec 11 04:46:10 hirsute-server pulseaudio[1967]: No such profile: output:hdmi-stereo
Dec 11 04:46:10 hirsute-server pulseaudio[1967]: Failed to initialize daemon due to errors while executing startup commands. Source of commands: /etc/pulse/>
Dec 11 04:46:10 hirsute-server systemd[1958]: pulseaudio.service: Main process exited, code=exited, status=1/FAILURE
Dec 11 04:46:10 hirsute-server systemd[1958]: pulseaudio.service: Failed with result 'exit-code'.
Dec 11 04:46:10 hirsute-server systemd[1958]: Failed to start Sound Service.
Dec 11 04:46:10 hirsute-server systemd[1958]: pulseaudio.service: Scheduled restart job, restart counter is at 1.
Dec 11 04:46:10 hirsute-server systemd[1958]: Stopped Sound Service.
Dec 11 04:46:10 hirsute-server systemd[1958]: Starting Sound Service...
Dec 11 04:46:11 hirsute-server pulseaudio[2087]: No such profile: output:hdmi-stereo
Dec 11 04:46:11 hirsute-server pulseaudio[2087]: Failed to initialize daemon due to errors while executing startup commands. Source of commands: /etc/pulse/>
Dec 11 04:46:11 hirsute-server systemd[1958]: pulseaudio.service: Main process exited, code=exited, status=1/FAILURE
Dec 11 04:46:11 hirsute-server systemd[1958]: pulseaudio.service: Failed with result 'exit-code'.
Dec 11 04:46:11 hirsute-server systemd[1958]: Failed to start Sound Service.
Dec 11 04:46:11 hirsute-server systemd[1958]: pulseaudio.service: Scheduled restart job, restart counter is at 2.
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