on my battery-based i.MX28 board with SGTL5000 codec and kernel 18.104.22.168 I change the cpu frequency on the fly (for powersave purposes).
The used soundsystem is ALSA.
All works fine and I can play any wave file with "aplay".
But if the CPU frequency changes while "aplay" is playing, sometimes "aplay" stops.
In this case the status of the "aplay" process is S (sleeping).
To change the CPU frequency I use the follwoing commands:
echo performance > /sys/devices/system/cpu/cpu0/scaling_governor
echo powersave > /sys/devices/system/cpu/cpu0/scaling_governor