I won't make excuses for a bad idea/design but a full power off/removal and unplugging all HDMI cables can let the interface reset.
This has worked many times and I can't supply links about it every time it comes up. Try it and hope.
I was watching Netflix on my HDTV last night using an HDMI cable connected to my Macbook when the connection suddenly was lost and my tv/computer weren't recognizing each other while the cables were still plugged in. I normally get the connection running through HDMI4 but it wasn't working. Then today I tried to start up my Playstation 3 through HDMI3 but again it wasn't working. What could be causing this problem? No cables seem to be unplugged so it's all very strange. If anyone has any tips I would love to hear them- thanks!