acd_setchan
error = acd_setchan(dev, arg->patch[0], arg->patch[1],
error = acd_setchan(dev, CHANNEL_0|CHANNEL_1, CHANNEL_0|CHANNEL_1, 0,0);
error = acd_setchan(dev, CHANNEL_0, CHANNEL_1, 0, 0);
error = acd_setchan(dev, 0, 0, 0, 0);
error = acd_setchan(dev, CHANNEL_0, CHANNEL_0, 0, 0);
error = acd_setchan(dev, CHANNEL_1, CHANNEL_1, 0, 0);
static int acd_setchan(device_t, u_int8_t, u_int8_t, u_int8_t, u_int8_t);