As far as I can recall: some internal implementation documentation leaked which made the legal position tougher for them somehow to protect it as proprietary (it made sense when I heard it explained, but now I feel like I'm missing an important detail to that), and then Valve had some talks with the HDMI Forum to convince them to let it go, presumably so they could have such support integrated into Linux for their hardware (Deck, Machine, Frame, etc).

So now the HDMI Forum just doesn't really care anymore I guess.

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gary_0 2 hours ago | parent [-]

IIRC, a non-AMD contributor was working on adding HDMI 2.1 support to Linux's AMD driver, and then AMD managed to get the HDMI Forum to see that their position was moot and was making things very awkward for AMD.

	▲	mort96 an hour ago \| parent [-]
		Oh this makes sense! Obviously, it can't be illegal for a non-forum-member to add HDMI support; it's just an HDMI forum policy after all, not law. That's certainly the link I was missing for this to make sense.