If writing to the configuration space manually, special consideration needs to be given when writing to PMA_CTRL2, PCS_CTRL2 and PCS_ABILITY via the DRP or Management Interface. When writing to these attributes, ensure that PCS_ABILITY is written first, then PMA_CTRL2 or PCS_CTRL2.
In the general case, GTHINIT is used to load the configuration memory of the GTH Transceiver. Because of the above dependencies in the write order between attributes, GTHINIT needs to be issued a second time following GTHINITDONE. This allows attributes that need to be configured first to be loaded prior to other dependent attributes, regardless of the write order determined by the internal circuitry of the GTH.