Various audio problems: ADC input source & Bad audio in mic.

[skoylu]

I'm use A20-SOM boards for various projects with a custom board. I can connect mic to A20 directly, with MIC1 in. Generally no biggest problems occurred; capture is good, play is no problem

But, i want stop capture from microphone. Many documents say: "Use amixer with 'ADC Input Muxer'". But new kernels can't show 'ADC Input Mux" in alsa controls. Yes, i can try directly write to A20-CODEC registers, but this very dangerous way

Another problem occurred in begin of capture. In system operated, we talk to microphone. For first 3-4 seconds, voice is very bad and too low. After 2-3 seconds, sound can be good, without any interaction from user. This case cannot change with used software, arecord|aplay, PJSIP or other ways.

If you know any reason for this problems and solutions, please help me.

Thanks.