Implementation of Tri-speed GMII interface fails in MAP due to not being able to place a clock pin and BUFG in the same half of the device. When a design with EMAC0 and EMAC1 configured with Tri-speed GMII interface is implemented, it fails in MAP with the following error:
"ERROR:Place:592 - A clock IOB / BUFGCTRL clock component pair have been found that are not placed at an optimal clock IOB / BUFGCTRL site pair."
To avoid this error, add the following constraint in the UCF:
INST "mii_tx_clk_0" LOC = "BANK3";