acd_start_stop
if (!(error = acd_start_stop(dev, 3))) {
acd_start_stop(dev, 0);
error = acd_start_stop(dev, 2);
error = acd_start_stop(dev, 1);
error = acd_start_stop(dev, 0);
static int acd_start_stop(device_t, int);