DAC_PRECH
retval = snd_at73c213_write_reg(chip, DAC_PRECH, 0x00);
retval = snd_at73c213_write_reg(chip, DAC_PRECH, 0xff);
retval = snd_at73c213_write_reg(chip, DAC_PRECH, (1<<DAC_PRECH_ONMSTR));