DS90UB926QSEVB: Bypass the DS925 video to DS926 EVB

Dear Sir:
        1. I can output test pattern(RGB888 60Hz) of DS926 EVB to TP6817 EVB, and TP6817 EVB bypass the RGB888 video to RGB888 panel, it                works  fine.(see Test 1 in the figure)
        2. I have a DS925 video source(from previous project in my company), it is connected to DS926 EVB through J1(Rosenberger HSD

            connector),
            If we want to bypass the DS925 video to DS926 EVB, I try to set I2C register, but no PCLK/VS/HS/DE appear on the oscilloscope(see Test              2 in the figure)
            how do we set DS926 I2C register table? Would you provide the initial register table for reference? thanks!!