chn_setvolume_multi
chn_setvolume_multi(c, SND_VOL_C_MASTER, left, right, center);
int chn_setvolume_multi(struct pcm_channel *c, int vc, int left, int right,
chn_setvolume_multi(ch, SND_VOL_C_PCM,
chn_setvolume_multi(ch, SND_VOL_C_PCM,
chn_setvolume_multi(c, SND_VOL_C_PCM, left, right, center);
chn_setvolume_multi(c, SND_VOL_C_MASTER, left, right,