hello if i use 1.8V at PHY ,then i should use 1.8V at imx6 ,I want to communicate via RJ45 as pic below.

but i find when i use 1.8V ,the bit of MODE[2] Rxclk should be 1 as pic below.

That is the mode is x1xx,and there is no mode can access 1000M speed。
Am I wrong?What should I do?