A video signal for a 2560x1440 @ 60 Hz resolution would have a PCLK that is too large for the UB688. The UB688 has a max PCLK of 210 MHz with dual link and your resolution and refresh rate would require at least 220+ MHz depending on the blanking required for your panel. You can either drop the refresh rate to something like 30 Hz to lower the PCLK, or you can go with a device that can use higher PCLKs such as the UB988.
