If the RXP and RXN differential traces are accidentally swapped on the PCB, the differential data received by the GTY and GTYP transceiver RX is reversed. The GTY and GTYP transceiver RX allows inversion to be done on parallel bytes in the PCS after the SIPO. This is done to offset reversed polarity on the differential pair. The polarity control function uses the CH*_RXPOLARITY input, which is driven High from the interconnect logic interface to invert the polarity.