TMDS261 : clock detection

I think I understand what you are asking for.  You could look at the HPD signal on the inactive ports to indicate if a source has been connected.  The TMDS signal actually will not be present until the input is switched, since the TMDS interface is CML that is terminated at the sink device ie: TMDS261.

Hope that helps

I'm agree with your advice, but I'd like to know how to detect through TMDS261's register access. HPD signal monitoring needs extra hardware or GPIO assignment.

Our TMDSx61 family only detects clock on the selected input.  All other inputs are off to save power.  HPD is the only way I can think of with the use of our device.