MPU401_RX_EMPTY 53 sound/drivers/mpu401/mpu401_uart.c (!(mpu->read(mpu, MPU401C(mpu)) & MPU401_RX_EMPTY)) MPU401_RX_EMPTY 40 sound/pci/oxygen/oxygen_lib.c return !(oxygen_read8(chip, OXYGEN_MPU401 + 1) & MPU401_RX_EMPTY);