Why does the VoIP_Framework_TX.vhd sdi_gtxrstdone signal have multiple drivers?
This is a known issue that will be addressed in a future version of the XAPP1199 reference design.
You can work around this by making the following change to the tx_change_done assignment:
LINE 1034 - .rx_change_done => sdi_gtxrstdone,
LINE 1047 - .tx_change_done => open,-- sdi_gtxrstdone,