Alex Deucher:
The HDMI Forum has rejected our proposal unfortunately. At this time an open source HDMI 2.1 implementation is not possible without running afoul of the HDMI Forum requirements.
So that means if we ever have an open source NVIDIA driver that matches the proprietary I won’t be able to connect my 4K screen @ 120hz via HDMI (as the only option) because made up rules by an HDMI faction of TV manufacturers say so?
yup, we need brands making TVs with DisplayPort.
UPDATE
Even though AMD might not be able to add support for HDMI 2.1, nouveau certainly will as Nvidia’s open source driver also supports HDMI 2.1 so there is no reason to believe that at least some drivers can’t support HDMI 2.1. It’s quite backwards, but apparently having all the logic inside firmware (like Nvidia does) will probably help us implementing support for HDMI 2.1 🙃"
https://www.phoronix.com/news/NVIDIA-Firmware-Blobs-HDMI-2.1