LOL.

I've written a couple of new ioctls so userland app can set the tones. I see this as being the way to go - anything really useful coming from this work will be too big to really live in the kernel. That being said, a simple hijack interface could probably be implemented, but I don't see much value in manually selecting/entering a single frequency at a time.

Much more valuable is a means to automagically step through a set of tones so that the response can be measured and noted down.

Even more valuable would be if I could also implement the microphone input, and automatically take peak measurements as well.

It would then be totally cool if a userland app could take the measurements, do some math with them and calculate an eq to flatten the system, and then write that to the empegs data partition.

As you can see, the dream lives in userland, but I am making kernel changes to support that.

At the moment I need to work through a couple of quirks. Specifically removing transient clicks at the start and end of the tone, and adding channel selection to the ioctls. Then I'll release a test kernel and some small command line test utils.