I have no intention of buying any kind of dongle / adapter.
My Surface Pro is able to display the screen on the tv for a second or two which proves it DOES NOT NEED AN ADAPTER.
If it needed an adapter it would never be able to show on the tv screen at all.
Period.
Since it can, and does indeed mirror to the tv for a brief period, that means SOMETHING is stopping the mirroring that had already begun.
The tv is sitting there with a black screen and it < thinks > it is mirroring --- just not getting a signal.
So either the Surface Pro tablet is stopping the mirroring ( Microsoft's fault ) or the tv is comparing the source of the mirroring to its list of allowed devices and saying ' whoa wait a minute the Surface Pro isn't on the list of approved devices so I can't let you mirror ' and stopping the video signal but not exiting mirror mode.
Since it will work if I only BUY ANOTHER PIECE OF MICROSOFT EQUIPMENT -- their adapter --- it appears to me that Microsoft has deliberately stopped the Miracasting to force us to buy their adapter.
The tv is still in mirror mode and DID show the Surface Pro screen until the Surface Pro stopped transmitting a valid signal.
Microsoft has the Surface transmitting some < modified > signal that requires the adapter to work.
I blame Microsoft completely at this time. Because they are the ones who profit with this setup.
I don't NEED to mirror to the tv but it would be nice to be able to.
Since I believe Microsoft has done this deliberately to force us to buy adapters --- they can stick it where the sun don't shine.