Reported by Nikolaus Schaller, Jul 22, 2019
the twl6040 can tell the audio subsystem that there is some DC offset in the class D amplifiers. But this is not taken care of by the McASP/BSP drivers. The result is that the speakers are driven with DC offset which has negative effects: * higher energy consumption than needed * membrane is already deflected in 0 position * loud sound may make the membrane run to the mechanical end positions which gives a very scratchy noise Solution: read out these registers and make the OMAP subtract the offset from the data before it is sent through the serial interface. It may be that the AESS could handle that better, but we do not have AESS up and running.
Sign in to reply to this comment.