I uses QSA to play audio files (demo application "wave.c").
I have no problems with QSA initialization and with writing file data to audio device, but I have problems with volume:

snd_mixer_group_t.min == 0 (min volume level)
snd_mixer_group_t.max == 0 (max volume level)

so I have zero volume level and can't change it.
What must I do to get nonzero max volume level?