huge mixers

[Philippe Bekaert]

Dear all,

I am working on a new driver for the RME HDSPe cards, which eventually could replace the hdspm driver. 

These cards have a hardware mixer / matrox router, freely mixing tens of hardware inputs and software playbacks into tens of outputs (8192 mixer controls on the HDSPe MADI).

Right now, mixer state (cached by the driver) can be read efficiently in one ad-hoc ioctl call, and individual channels modified through a HWDEP ALSA control element with 3 parameters (input/playback index, output index, gain value).

I understand there is a desire to get rid of ad hoc ioctls and am therefore looking for a more generic way to read and write huge mixer state. 

Has anyone been facing similar issues? How have you been solving it? Is there any “common practice” or “habits” in this community concerning this topic? Would it make sense to define a kind of generic huge mixer interface? Then, has anyone an idea or preference how it should look like?

Looking forward to your feedback.

Best regards and thanks in advance,

Philippe.