CYCLON IV GX - ALTGX Won't recieve any valid data

-when we ignore freq_locked, we still get a constant ffh,

-we are using quartus 11.1

-we are constantly interchanging the boards to assure this is an issue with the code/ hardware rather than a specific board.

-I checked the datasheet and it seems that while the altgx supports Lvds, it's with an 0.82 vcm so it is probably holding a constant '1', the optical transciever is AC coupled so sending a constant bit will simply disconnect it which is why we thought t he fpga gets valid data.

Is there anything we can do?