triple speed Ethernet，the mac not output when tx is enable

[Altera_Forum]

i am using tse to connect with 88e1111, working at 1000M mode, rgmii. now i can receive frame from pc,but when i send frame to the avalon interface, the core output ports rgmii_out and tx_control is always 0. i have rd the mac_configure register 0x02,the collision signal is always deasserted. i also read register 0x1A, aFramesTransmittedOK, which indicate the number of frames that transmit successfully, it changes when i send frames. 

i also enable the loopback of the mac, it works correctly. i can receive the data exactly the data that i send. so what will affect the tx function of the mac? why the tx_control signal is always deasserted? any advice is appreciated. i have been confused with this problem for days.

[Altera_Forum]

Hello josh_zhou, 

 I'm having a similar problem on an Arria V starter kit. Did you ever find a solution to the problem? I've been posting here on the forums, but I have yet to get any useful responses.

[Altera_Forum]

You can try to add phase shift to the tx clock. I fixed this problem by this method.

[Altera_Forum]

Thanks for the tip. How did you determine what phase shift to use?