I’m using manjaro with KDE Plasma and PipeWire. The sound output through HDMI suddenly stopped working, sound through internal speakers or Bluetooth device still works. I have not changed anything and not installed an update. It just happened. Correct output device is selected in KDE and shows visual feedback when sound is played. Rebooting doesn’t solve the issue.
Any ideas what could be the cause or where I could start looking?
Wow, that worked, I had to disconnect the power to the monitor though.
Before that I had tested with another computer that is also connected to the monitor via an HDMI switch, which is also the reason I connected my speakers to the monitor, but I never thought to turn off the monitor. I don’t understand why it makes a difference, but I’m just happy it’s working again.
I just gave you the instructions written on this Arch wiki, and the cause of your problem is:
If aplay does not output any errors, but still no sound is heard, “reboot” the receiver, monitor or tv set. Since the HDMI interface executes a handshake on connection, it might have noticed before that there was no audio stream embedded, and disabled audio decoding.
You can go further and set your HDMI as default by adding/editing config file ~/.asoundrc, but you need to revert the change when you unplug your external HDMI device/monitor.