am 44adf098: am 938c31c0: change LinearityTest algorithm to use RMS of the whole signal and use linear regression to fit the result volume level is fixed to 2/3 of max

* commit '44adf0985857c51df143a830f2b6ff8beacd73ec':
  change LinearityTest algorithm to use RMS of the whole signal and use linear regression to fit the result volume level is fixed to 2/3 of max