One of the limitations of the AMDGPU Linux kernel graphics driver has been the lack of its support for HDMI 2.1 and later. AMD has wanted to support HDMI 2.1+ functionality under Linux but it’s been legally blocked by the HDMI Forum. But anxious independent users have been working on open-source patches for wiring up HDMI 2.1 into the AMDGPU driver outside of the realm of AMD and the HDMI Forum’s blessings. ……
The HDMI forum is made up of those TV manufacturers, so I doubt they’d help push an open standard that’d earn them less.