help: Genlock Function of CVO

I start to evaluate the Genlock function of CVO, but it can not lock to the source.

(It is based on the UDX2_1_LABS lab3 from Altera; and Arria II GX Devkit+ HSMC-SDI)

In the SOPC, CVI(sdi_in_1) connected to terminator, Test Pattern Generator connected to CVO(sdi_out_1).

Outside the SOPC, sof and locked_sof from the CVI connected to CVO.

In the Nios software, the_sdi_out_1.set_genlock(true) to enable CVO genlock function, but when read the status of CVO, it always not genlocked (the_sdi_out_1.is_genlocked()).

The format of sdi_in_1 is PAL, and TPG and CVO is also set to PAL.

I check the sof from the CVI, it is a 25Hz pulse, it should be OK.

I check the CVO (sdi_out_1) output by SDI monitor, and it is OK.

Please help me!

Thanks.