Allo Piano 2.1 Sub volume not linked to Master volume (Pi 4B + volumio 3 + Spotify )

[ashthespy]

@MightMess

So I don’t know. It’s not a board thing I think as when using “Sub” as Mix Control Name, the volume can be controlled but otherwise, in “Master” as Mix Control Name, all modes have the same issue.

Perhaps I’m being daft - As far as I can understand from Allo’s docs (and the driver code - linux/sound/soc/bcm/allo-piano-dac-plus.c at rpi-5.10.y · raspberrypi/linux · GitHub) you need to choose the Master Playback Volume to change volume for both outputs.

IIRC this might also be related Piano 2.1 left channel broken - #9 by ashthespy

From seeing how Volumio’s volume logic tackles this case (essentially just sets Digital and then checks for this DAC and sets Subwoofer volumio3-backend/app/volumecontrol.js at 8dc851370bb529cc1e945f7fcc025597bcd7189a · volumio/volumio3-backend · GitHub), using the Master Playback Volume should technically do the same, but at the ALSA driver level which should be much more efficient than the current way. Or am I missing something obvious here?