A quick update: The ALSA audio project for Linux has a utility called alsaloop, which provides an audio loop back through “capture” and “playback” interfaces. On the Toradex Apalis iMX8 platform, using alsaloop, I was able to play an instrument in a loopback configuration with an analog “line in” and a headphone jack. This is a huge deal, because it allows for an analog-in to digital to analog out path, and a great embedded device for building a complex effects processor!👍 More work to follow!