DP83867IR RX_DV/RX_CTRL Strap pin MODE description

Hi,

I have a question about DP83867IR Strap Pin "RX_DV/RX_CTRL".

This "RX_DV/RX_CTRL" is strap pin for "Autoneg Disable" setting and
we can select MODE3 or MODE4.

If I want to enable Auto Negotiaon, which mode is correct?
In DP83867IR datasheet, there was no description about MODE3 and MODE4 of RX_DV/RX_CTRL strap pin.
So, I don't know which mode to select.

best regards,
g.f.