When the far end stops transmitting or powers down, the GTX receiver requires a reset on the resumption of data transmission. This is done by adding the code below to drive the signal 'mgt_rx_reset' in the block level source file.
This solution applies to the XAUI v10.2 or RXAUI v2.2 core with Kintex-7 or Virtex-7 GTX transceivers when using Initial ES or General ES silicon. This code will be added to the next release of the cores.
localparam SYNC_COUNT_LENGTH = 16;