I'm going to share some information that I think can be valuable to alot of people. I've had a problem with my TV that I've plugged in with HDMI from my desktop computer. From time to time when I started the clone desktop and/or extend desktop onto panel, it just started flickering. The TV wasn't able to "snap" and the monitor showed my desktop for a second, then went dark again. It then gets stuck in a loop and does this over and over again.
Appearantly, this TV sometimes resets the maximum supported resolution down to 1366x768. So, first I tried to lower the output resolution, which strangely didn't work at all. I needed to find out if there was a way to reset the EDID data and bring back the max value up to 1920x1080. After some research, I suppose that's possible, with extracting Hex EDID data and re-coding it manually. At least that's what I gathered from a few guides I found floating around.
Problem for me was that I didn't really feel like doing this advanced kind of stuff that I really don't know much about, so I needed another way to set the correct values.
These are some different solutions to this this issue that I've picked up that might be able to help you. Most of the time I've only needed one of these ways to get it working.
1. In Catalyst there's a way to just manually set the maximum supported hz and resolution of your TV. The sub menu with the EDID values didn't pop up for me at all with just the HDMI cable plugged in, so I plugged in a regular VGA as well, which strangely made the sub menu available. Then I just put the max resolution back to 1920x1080 and I was able to Extend my desktop in 1080p with just the HDMI cable. The sub menu should be easy to find in Catalyst once you've plugged in the VGA cable.
2. On my other computer that uses an Nvidia card I didn't have any native HDMI port, so I used a DVI->HDMI adapter. Then I just needed to activate the sound output for the TV in the Nvidia Control Panel (It was inactivated by default) and the EDID data seemed to reset.
3. Use a DVI->HDMI adapter on a DVI slot on your graphics card and plug the HDMI cable in to it. Clone or Extend the desktop onto the TV and it seems like this resets the EDID data. In my case it says something about ATI Overdrive overclocking failure (If I remember correctly) and it just starts working.
4. Just change the Hz value to the maximum supported one for your TV. This has helped from time to time during the few years I've had the privilege of using this garbage TV.
5. Re-installing the ATI HDMI Audio Driver has made the it work once or twice during the time I've had the TV too.
Hope this information is valuable to at least someone