[LAD] huge mixers

Philippe Bekaert linux at panokkel.be
Wed Aug 18 17:27:44 CEST 2021

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 / matrix 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 driver <-> user space API to read and write huge mixer state. 

Does such more generic huge mixer interface already exist? Has someone been facing this or similar issues in this community? If not, are there any ideas, suggestions or preferences how it should look like?

Looking forward to your feedback.

Best regards and thanks in advance,


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