SB_DSP4_MPUSETUP
mpureg = snd_sbmixer_read(chip, SB_DSP4_MPUSETUP) & ~0x06;
snd_sbmixer_write(chip, SB_DSP4_MPUSETUP, mpureg);
realmpureg = snd_sbmixer_read(chip, SB_DSP4_MPUSETUP);