Hi,
I've build my own libreelec device: amd64, based on Dell Wyse thin client, AMD CPU.
This has only stereo output, so I can add USB 5.1 card to the setup.
I have cheap one, identified as
Bus 003 Device 010: ID 0d8c:0102 C-Media Electronics, Inc. CM106 Like Sound Device
Unfortunately, it plays only stereo, via Front output. Rear and Center/Sub are completely quiet. I can tune their volume via alsamixer, but they are still without sound
I've checked the device with another linux machine (current linux mint) and it works like a charm. So - device is fine and there is correct driver in the kernel.
In alsamixer I can see and do completely the same as on linux mint system, so it looks ok.
Of course from Kodi side I've set correct output device and 5.1 output.
Some time ago there was an addon - Kodi Audio Mixer. Maybe it would help, but it doesn't work for me now - I see long list of outputs without any description.
What to do?
EDIT: reg to Kodi Audio Mixer - installed it and moved all gauges one by one (there is about 20). No change, still only stereo.