ADAU1787 HP_CTRL line out vs headphone output (HP1_MODE, HP0_MODE settings)

I am:

1) connecting the DAC output to low impedance ear bud speakers
2) looping the DAC outputs to the ADC inputs

When I switch (in real-time) between the HP_MODE line out and headphone out settings, I do not see any change in signal level neither case 1 nor case 2 above.

Other than the PB1_EN, PB0_EN, are there any other bits to make this setting functional?

Can I modify the setting in real-time?

I know the I2C interface is working in that my init works and my switch logic works for DAC mute (in real time).

How can I test whether this feature is working?

Thanks,

Dan

HP_CTRL

ADAU1787

Integrated/Special Purpose A/D Converters

headphone

Audio CODECs