I'm running Android P (2.3.4) on iMX8MQ and trying to use an external USB camera. I haven't seen anything that implements the Camera2 external camera config (External USB Cameras | Android Open Source Project ) but I do see the USB camera enumerate as a UVC camera (and messages from the FSL HAL). Is there documentation on how the camera frames are being read from the external cameras if not the Android CTS external camera suite? The default camera app doesn't support this (just front/rear cameras)/
you can set it in init.rc like below:
setprop back_camera_name uvc
that is to say , modify front or rear to uvc
then you run campera apk to preview it.
Hope above information can help you!
Have a nice day!