Enable the debugging log in the pulsaudio:
edit /usr/lib/systemd/user/pulseaudio.service, comment out the line starting with ExecStart=..., add a new line "ExecStart=/user/bin/pulseaudio -vvvv --log-target=file:/home/your_user_name/pa.log
reboot
Then tail -f ~/pa.log
Plug the hdmi monitor, and select the hdmi audio as output device from UI. now check the pa.log, could you find the "configured_default_sink" from the log, it indicates the change of configured_default_sink.
If the hdmi audio is set to configured_default_sink and keeps unchanged during the suspend and resume, the hdmi audio should be the output device after resume. So please check the changing about configured_default_sink in the pa.log.
So, let's debug with the pulseaudio log.
Enable the debugging log in the pulsaudio: systemd/ user/pulseaudio .service, comment out the line starting with ExecStart=..., add a new line "ExecStart= /user/bin/ pulseaudio -vvvv --log-target= file:/home/ your_user_ name/pa. log
edit /usr/lib/
reboot
Then tail -f ~/pa.log
Plug the hdmi monitor, and select the hdmi audio as output device from UI. now check the pa.log, could you find the "configured_ default_ sink" from the log, it indicates the change of configured_ default_ sink.
If the hdmi audio is set to configured_ default_ sink and keeps unchanged during the suspend and resume, the hdmi audio should be the output device after resume. So please check the changing about configured_ default_ sink in the pa.log.