sum_desc
const struct sum_desc *desc,
const struct sum_desc *desc,
const struct sum_desc *desc, struct sum **rsum);
struct sum_desc sum_dsc = {0};
struct sum_desc sum_dsc = {0};
struct sum_desc sum_desc = {0};
sum_desc.msr = mixer->atc->msr;
err = sum_mgr->get_sum(sum_mgr, &sum_desc, &sum);