Can I use a transceiver RX Pin as a Tx PLL REFCLK for the HDMI Design Example transmitter interface (Source) on Arria 10 and Cyclone 10 devices?

No, you cannot use a transceiver RX Pin as a Tx PLL REFCLK for the HDMI™ Design Example Transmitter Interface (Source) on Arria© 10 and Cyclone© 10 devices.

The HDMI Design Example Transmitter (Source) connects the REFCLK signal to the Tx PLL (fPLL) and an IOPLL used to generate the video clocks.

The RX Pin as a REFCLK resource cannot connect to an IOPLL. Your Quartus Prime design will fail to fit if you place the HDMI Design Example TX REFCLK on an Rx Pin.

To work around this problem you should place your HDMI Design Example TX REFCLK on a dedicated transceiver REFCLK pin.