The unplug and plug forces the HDMI handshake. This is not a cable issue but the HDMI chips in TV and card not playing well together under the scenario you have.
http://www.howtogeek.com/208917/htg-explains-how-hdcp-breaks-your-hdtv-and-how-to-fix-it/ notes a possible fix if you can't get the TV or card maker to fix it.
Bob is not a HDCP fan.
I recently upgraded the video capabilities of the PC connected to my Sharp Aquos TV and I've encountered some perplexing issues:
1. When I switched the HDMI cord from the Intel built-in graphics to the AMD R7 240 card, the TV would become green when switching it from cable TV to PC. There were no problems going the other way (PC to TV). None of this was ever a problem with the built in Intel graphics.
2. When I would unplug the HDMI cord from the video card and plug it back in, PC graphics would return just fine.
3. I bought a new HDMI cord, updated to the latest standards, and plugged that into both the TV and PC card. Now, the monitor goes black (rather than green) when switching from TV to PC.
The only solution is to unplug the HDMI cable/cord from the back of the PC and plug it back in. Alternately, I can reboot the computer itself.
I am truly perplexed. BTW: I'm running all of this on a Dell Vostro 270 with Windows 10 Anniversary Edition.
Any help anyone could give would be greatly appreciated. I've searched the web and found nothing that really mirrors what I'm experiencing.