MII connection checks between a NS9210 and a PHY

I would like to check if the the MII connection between my NS9120 and an Ethernet switch (A Micrel KSZ8873) is accurate.
Is there a means for that ?
I found the MII Management Indicators Register in the datasheet. It features a MIILF (MII link failure) bit, but documentation is weak :

When set to 1, indicates that the PHY currently has a link fail condition.

Does anybody have more information?