I have a problem with audio using a USB-C to HDMI connection from my Dell XPS15 7590 on Ubuntu 18.04. I have an ASUS VP28UQGL external monitor to which I am connecting my laptop and an Apple TV. The monitor has an audio output, so I connected my speakers to it in order to have audio for both devices easily through HDMI.
I tried 2 configurations:
Connecting my laptop to the screen using the HDMI output port of the laptop. Here, the audio works great. However, whenever I lock my screen (I don't go to suspend), it turns off the monitors, and when I log back in, Ubuntu detects the external monitor, but the external monitor acts as if it has no input source (it displays no source). I have to plug out the HDMI cable, change sources or do some other things in order to get the monitor to detect the laptop.
Connecting my laptop to the screen using a USB-C to HDMI mini-dock (LMP 14368). Here, I don't have any problems with the monitor. I lock my screen, and it unlocks without problems, on two screens. However, in this configuration, the audio over HDMI doesn't work. Or works sometimes, basically randomly.
So my question is, did anybody have a similar problem with the audio not working over a USB-C to HDMI mini-dock? And if yes, how was it solved?
Thank you in advance!