Xuebing Wang wrote:

I am developing a commercial product based on Freescale iMX6SL + UAC2.

I can get UAC2 working for below command. 'hw:1,0' is the virtual sound card. 'hw:0,0' is the physical sound card. export RATE=44100; arecord -D hw:1,0 -c 2 -r $RATE -f S16_LE | aplay -c 2 -r $RATE -f S16_LE &

Any suggestions on what is the best way to get PCM stream from UAC2 virtual sound card and feed to the physical sound card?

This will not work unless the clocks of the virtual sound card (i.e., the USB bus clock) and the clock of the actual sound device are synchronized.

Otherwise, you have to write your own UAC2 driver.

Regards, Clemens