chn_setmute_matrix
ret |= chn_setmute_matrix(c, vc, i, mute);
ret |= chn_setmute_matrix(c, vc, i, mute) << 8;
ret |= chn_setmute_matrix(c, vc, i, mute) << 16;
int chn_setmute_matrix(struct pcm_channel *c, int vc, int vt, int mute);