I2S aplay /dev/zero script blocks playback: "Device or resource busy"

[besi]

I did run the installer script for the I2S Class D amp and everything did work fine right from the start.

However, if I do enable the option activate '/dev/zero' playback
then I get an error when attempting to playback some audio:

aplay: main:788: audio open error: Device or resource busy

Could it be that only on instance can be using aplay at any given moment?

See i2samp.sh#L450

/usr/bin/aplay -D default -t raw -r 44100 -c 2 -f S16_LE /dev/zero

[ladyada]

no, you can def run more than once. try rebooting

[edmcdonagh]

I have this same issue - unless I kill the systemd aplay service I can't play anything - aplay: main:828: audio open error: Device or resource busy

I have rebooted multiple times, but the only solution so far is to kill the service or to disable it.

The same is true if I try an aplay two wav files simultaneously - what is it that makes aplay accept two inputs?

I'd be grateful for any pointers!