[popcornmix]

Files are PCM MCH
Please find the first log here
You could notice;
- After switching on Pi I tried to play one file but I had no sound at all. I had to change the video resolution from 720 to 1050 and sound want back. This occur very often when I start the device. I didn't post about that so far. (if you can read why this issue could be good)
- First I played 1 file with 5.0 config
- Second I played 2 files with 2.0 config

File is AC3
The second log here
- I did a reboot and I had to change the resolution to 720 to get sound
- First I played 1 file with 5.0 config
- Second I played 1 file with 2.0 config

First log is a wav file with PCM. Only DTS and AC3 support passthough, so this doesn't use passthrough. Therefore speaker configuration does have an effect.
Second log is AC3 audio. Passthough is correctly being used. Therefore you will have multichannel audio whether speaker configuration is set to 2.0 or 5.0.