CHN_N_TRIGGER
flags &= CHN_N_VOLUME | CHN_N_TRIGGER;
if ((flags & CHN_N_TRIGGER) && !(c->flags & CHN_F_VCHAN_DYNAMIC)) {
flags &= ~CHN_N_TRIGGER;
if (flags & CHN_N_TRIGGER) {
ret = chn_notify(p, CHN_N_TRIGGER);