And since version 1.2, DisplayPort is a superset of eDP. And this is not just theory, people actually tried running iPad eDP screens off their graphics cards' DP outputs. And guess what? With DP 1.1 that didn't work, but with DP 1.2 that worked with minimal circuitry.
All I'm saying is that if your hardware already supports VRR via eDP, then your hardware has everything it needs for supporting VRR via DP.
It just proves that FreeSync/Adaptive-Sync on DP and FreeSync/Adaptive-Sync on eDP are functionally the same.
You are wrong here too. Kaveri is second generation GCN. There are no APUs of first generation GCN (Bobcat is VLIW5, Trinity/Richland are VLIW4, and Kaveri/Kabini are GCN2),
Also your claim that 7970 doesn't support FreeSync is false. It supports FreeSync for video playback, but not for gaming.
First my apologies, I meant Kabini not Kaveri. I am always getting the two of them mixed up. Kabini is first generation GCN. (If you check, it uses GCN 1.0, not 1.1)
I never said Freesync on eDP and DP were functionally different. They shouldn't be as the Display port adaptive sync is based entirely on the eDP spec. What I am saying is that Just because a GPU has a 1.2a or 1.3 or 1.4 or whatever display port, doesn't mean it supports Adaptive sync. The GPU manufacturer still has to make a choice to use the OPTIONAL adaptive sync hardware or not. But any Laptop GPU or any APU that uses eDP 1.2 or higher has to support VRR and because of that work with adaptive sync.
Also I don't think If you have a GPU that supports VRR through eDP, means it will have support for VRR via DP. Remember when Nvidia announced Gsync for laptops? They made Maxwell cards that supported LVDS and eDP. The GPUs that went into the LVDS laptops did not support Gysnc, the ones that went into eDP laptops did. I remember reading on forums about people trying a 980M from a LVDS laptop in an eDP laptop and it didn't work with Gsync, they tried flashing the BIOS, spoofing the ID and everything, the card worked, but, Gsync didn't. While the silicon might be similar, there can be variations.
The 7970 doesn't support adaptive sync. What happens is when you play a video the drivers detect what refresh rate the video is playing it and then sets your monitor to a multiple of that. So if the video is 24hz, it sets the monitor to 48HZ. It's just a one time change and is made possible by the updated scaler in the monitor. It doesn't support VRR at all. It doesn't have the hardware.