DP83848M: 25-MHZ clock out start up

Dear community,

We are currently working on a custom board which is closely related to the TMDSIDKAM437x. However, we have decided to exchange the TLK105 Ethernet PHY transceiver with a DP83848M that incorporates a 25-MHz clock out thus eliminating the need and hence the space and cost, of an additional clock source component. As stated in the datasheet, we have connected the X1 pin (clock input) to the 25_Mhz_OUT pin and left the X2 pin floating.
To our best knowledge, there is no statement about how to even start this 25-MHz clock out. On power-up the clock source is on GND. Does anybody know how to start it or has encountered a similar issue?

Best regards,

Liliane