TX2 in my custom board, the volume displayed on HDMI always adjust defaultly without control

Hello Sir/Madam,

The TX2 in my custom base board,when it display with HDMI on the screen,the volume adjusts itself without control(volume up to the maximum).
Is there anyone knows which pin on the board relates to the volume controlling?

On the development board of TX2,only find the pin of SLEEP maybe can adjust the volume.

Thanks!

This is just a guess, but I suspect you’ll have to use something like ALSA mixer settings in software.