'Interface Mode' -turns off input processing, and functions as a USB sound card

[DiffractionCircuit]

Very similar feature request here:

Screen Off / Mixer mode

Hello everyone, I’m using my Quad Cortex also as a desk sound card. The thing with this is that the screen is always on and the device is getting pretty hot. In my opinion this doesn’t have to be the case when the screen is off. The screen generates a lot of heat in the device. Now I’ve got 2 feature requests. Screen off mode: When only using the QC as a sound card playing sound from my PC / whatever device is connected to the QC, the screen could be turned off only to wake up again when t…