High-Definition Media Interface technology, or better known as HDMI, is a media connection technology developed by the HDMI Forum as a technology standard for high-definition connections for various types of media and electronic devices.
HDMI 2.1 and HDMI 2.2 in particular come with connections that allow users to display video output at high resolutions and refresh rates, such as 4K at 120Hz and 5K at 240Hz and have various encryption support that is limited to the use of proprietary technology only.
In an interview with Ars Technica, Valve said that although the plug listed on the Steam Machine is HDMI 2.0, they said that the physical plug used is an HDMI 2.1 plug.
Unfortunately, the HDMI Forum, which is the developer of HDMI technology, does not allow the use of open source technology with the latest HDMI connection. Previously, AMD had asked the HDMI Forum to allow the HDMI 2.1 connection to be used with their open source graphics software, but was flatly rejected by the HDMI Forum.
Valve is said to be in talks with the party to allow open source driver software such as AMDGPU to be used with HDMI technology, especially since the Steam Machine uses AMD RDNA 3.5 graphics processing chips, but this discussion is expected to take time due to the strict specifications required by the HDMI Forum.
The chances for Valve are slim, but since the HDMI 2.2 standard has only just been introduced, the HDMI Forum may be more open to allowing open source platforms to use HDMI 2.1 technology that has been introduced since 2017.
If Valve is forced to only use HDMI 2.0 connections, the maximum resolution and refresh rate that can be matched with the Steam Machine is 4K resolution and 60FPS refresh rate by default.
