[Q] Get list of all settings available (even custom ones)

Hello,
I am having issues with a rom for a mini pc (Rikomagic Mk802 II).
Last firmware seems fixing a lot of issues, but there's just one bug.

When some app needs to access to microphone, it changes a setting (Audio Output, available in settings app).
To make audio in&out work, I have to manually access to settings and set it back to the proper value.

I would like to write a simple service that observes this setting and sets it back to a specific value. It will need surely root permission.
This class can help me in finding the setting? http://developer.android.com/referen...gs.System.html
I can make a query on the contenturi selecting all the settings and obtaining the right one?

Any advice?