So I have two PCs, one is old Intel/nVidia powered machine with DP output and basic HDMI 2.0. There I can do this.
Its done via Club3D active adapter. It runs at presumably 4:4:4 RGB and 12 bit output (I assume its 10+2, given panel itself is just 10 bit TV). Which also means that a) adapter works b) HDMI 2.1 on TV works.
On my Ryzen 4650G I can run only in 8bit colors. HDMI 2.1 and DP outputs are on motherboard MSI MAG B550M Mortar Wi-Fi. As for how real is that HDMI 2.1 on that mobo I cant say. DP on other hand Ive tested on other LCD and it works as it should.
When HDMI is connected between that mobo and TV, it doesnt display any bandwith and its limited to HDMI 2.0 functionality. Given it doesnt even display bandwith speed, I suppose there is some problem.
I tried two cables, one is even VESA certified 48Gbps (and pretty short, barely 1M). Neither of them help.
With adapter from Club3D I get at least 4x 5.4Gbps bandwith (which is surprise HDMI 2.0) info. And thats about it.
Adapter doesnt work, cause AMD drivers cant recognize its DP1.4 and has DSC. nVidia had same issue for quite a few drivers back. Originally adapter worked, then they upgraded DSC handling and backward DP support and broken it till like last month.
As you can see on the screenshots, adapter today works as it should with nVidia. And doesnt with AMD.
So AMD, be nice and investigate, please.
Also I would like to know why native HDMI 2.1 on motherboard doesnt work with HDMI 2.1 TV. Thanks.
I can supply EDID data, dumped it some time ago.
Im running latest AMD drivers obviously. I tried even previous ones, but no change.