You should take both your TB Display and your MBP into your local Apple Store or an AASP and see if the Display works with other MBPs - if it does, you'll know that the problem lies with your MBP TB connection. If it doesn't work with another MBP, then you'll know that it's the Display.
Mine just works - as it should. Your's should, too. Let Apple handle it rather than resetting SMC, etc., every time you want to use the ports. I'm using FW800, USB, Ethernet, etc., ports with no problems.
Well, Sadly I Bought a ThunderBolt Cable, extra And Works Perfect. So Now I will send my TD to the Services to change the Thunderbolt Cable OEM.
It's the Cable, not the MAC, not the Display, not the Logic Board of the TD, Not the Logitech USB Receiver, Not the Apple Keyboard wire, Nothing like that.
So, I Glad that my TD works ok, with other cable for now.