It’s not complete HDMI 2.1 support but to much surprise hitting the mailing list today were official patches from AMD for implementing HDMI Fixed Rate Link “FRL” support for their kernel graphics driver. HDMI FRL as part of HDMI 2.1+ allows for higher bandwidth to support higher refresh rates and resolutions.
Typical Phorinix. Wil not elaborate what FRL is.
The first paragraph:
How much more of an explanation do you need?