[IDEA] Automatically suspend USB DACs when idle

[sll552]

The RPi architecture is what it is. At least uhubctl is available in the Raspberry Pi OS repro these days and it appears from the github activity to be pretty solidly supported in the larger world. As you say, however, to use it with moOde would require an external smart USB hub.

Well it works with the internal Hub, but can only disable all Ports at once

My few DACs don't have a built-in display. If they did, however, my partner who is pretty particular about how any technology she uses should "just work™" would want them to behave consistently.

The feature (whatever it is, hooks or suspend) should of course be optional, so if you want your DAC to be always on, why not.

Given that MPD is only one of several renderers implemented in moOde, she'd want the display-blanking to work irrespective of the client UI in use. This means not just the moOde webUI but also the Spotify app on her phone and the Airplay connection from my iPad or UPnP or Bluetooth connections from my Android phone when using other clients. Then there's moOde users who drive the internal MPD server from an external MPD client.

This is actually something I missed completely, how is a scenario like "some device is streaming spotify and someone opens the webinterface" handled? Like what is displayed on the UI and what happens if you press play in the UI? Is there no interaction with moode code when some other renderer (bluetooth, spotify, etc.) is used?
I guess that it would still be possible to do by asking alsa if its currently doing something, but I have not looked at that. Or maybe some kind of socket monitoring or whatever, so if something connects via bluetooth, wake the DAC etc. But yes multiple render paths make it at least harder.