SV_DEVICES_PER_PORT
mute = (off % SV_DEVICES_PER_PORT);
idx = off / SV_DEVICES_PER_PORT;
cp.dev = SV_FIRST_MIXER + i * SV_DEVICES_PER_PORT + 1;
#define SV_LAST_MIXER (SV_DEVICES_PER_PORT * (ARRAY_SIZE(ports)) + SV_LAST_CLASS)
mute = (off % SV_DEVICES_PER_PORT);
idx = off / SV_DEVICES_PER_PORT;