Amixer says my device is mono:

root@phyCORE-MPC5200B-tiny:~ amixer Simple mixer control 'PCM',0 Capabilities: pvolume pvolume-joined Playback channels: Mono Limits: Playback 0 - 1023 Mono: Playback 942 [92%] root@phyCORE-MPC5200B-tiny:~

That's coming from the Volume control....

if (snd_mixer_selem_has_playback_volume(elem) || snd_mixer_selem_has_playback_switch(elem)) { printf("%sPlayback channels:", space); if (snd_mixer_selem_is_playback_mono(elem)) { printf(" Mono"); } else {

The device's master volume control controls all channels through one value. The device really is stereo. You use biquads if you want to process the channels differently.

What do I do about this?