Modify Ariia V ALTLVDS_TX data rate during work

The Arria V dedicated LVDS hardware does not have access to the clock mux. It uses a dedicated clock path from the LVDS block to the LVDS channels. Three clocks are used too, one for high-speed serial, one for the parallel clock, and one as a clock enable to load data between. You'll want to create the altlvds with an external PLL and then reconfigure that PLL. (I haven't fully checked if you can reconfigure it when in LVDS mode, but I assume so).

That's all if you're using altlvds. I thought 162 and 270 were your serial rates, but rereading, your serial rates are 1620 and 2700 Mbps. altlvds doesn't run that fast and you'll need high-speed serial I/O.