heres what happened.
I own a Sony STR-DN1080 Receiver/Amp into which all my HDMI devices connect into. It then is connected via HDMI to the TV.
However, when i bought my new Samsung QE65Q67RATXXU it simply would not communicate (handshake) via HDMI no matter what.
It actually sent the display on my Sony Receiver completely "gaga" ! i.e. flickering as if it was getting a loop-back signal of some kind. Occasionally it would sound-pop the odd noise as well , but no image. (TV said, NO Device)
I now believe this is just what it was...an HDMI loopback signal...because here is how I fixed it (or rather, came up with a "workaround")....
What i did was very simple. I simply added a powered HDMI splitter inbetween the Sony Receiver and the TV!
and everything just started to work perfectly! I believe the introduction of the HDMI splitter was now somehow "blocking" whatever signals the Tv was sending back to the Receiver - (probably trying to detect what it was so it could control it!!)
So, here you go. Hope this helps anyone else with a similar problem....
Sony Receiver - add a "powered" HDMI Splitter - TV
= working 100%
[update] - also tested a "directional one way HDMI lead but that did NOT work. Only the splitter has worked so far. I intend to try out an inline HDMI Extender/repeater (unpowered) just to see if that works. will post findings..