AMD preps “full” HDMI 2.1 implementation for Linux

AMD’s preparing to deliver a “full implementation” of HDMI 2.1 on its Open Source Linux drivers

Phoronix has confirmed that AMD has officially implemented HDMI Fixed Rate Link (FRL) into its Open Source Linux GPU drivers. HDMI FRL is part of the HDMI 2.1 standard and enables higher bandwidth display connections. This bandwidth, in turn, enables support for higher screen refresh rates and resolutions.

In 2024, the HDMI Forum rejected AMD’s HDMI 2.1 driver support plans for Linux. Basically, the HDMI Forus doesn’t want open-source drivers revealing details about its HDMI IP that it doesn’t want to be public. This has prevented AMD from delivering HDMI 2.1 support on its GPUs, which is a massive annoyance for Linux gamers.

Full HDMI 2.1 support is coming

On the Phoronix Forums, an AMD Graphics Driver Engineer has claimed that a “full implementation” of HDMI 2.1 is on the way. It will be “available once the patches are ready and have completed compliance testing”.

It is currently unknown what has changed to allow AMD to add HDMI FRL and other features to its Linux drivers. AMD has noted that “DSC is still being tested and will be sent out later”. Hopefully, nothing will halt AMD’s progress towards full HDMI 2.1 support on Linux.

This patch series adds HDMI FRL support to the amdgpu display driver. DSC is still being tested and will be sent out later.

This work passed a representative subset of HDMI compliance and a full compliance run on this branch is in the works. We don’t expect the full run to show any failures since it passes in other environments.

Thanks to Siqueira who prepared this work a couple years back and unfortunately didn’t manage to send them while he was still working at AMD.

Thanks to Jerry who has been making this code solid on Linux and running the compliance tests.

The first patch in the series isn’t related to HDMI 2.1 but included here because it moved the code around some key bits of the HDMI 2.1 stuff around too much. It will land with the next DC Patch series.

– AMD – via Phoronix

(An AMD Graphics Developer confirming plans for a “full implementation” of HDMI 2.1)

Was Valve the driving force behind this change?

Despite supporting HDMI 2.1 at a hardware level, Valve’s upcoming Steam Machine is listed as an HDMI 2.0 product. Why? The limitations are AMD’s Open-Source GPU drivers for Linux and the HDMI Forum’s overprotectiveness of its modern HDMI standards.

If AMD can deliver a full HDMI 2.1 implementation with its newest drivers and complete compliance testing, the Steam Machine will be an HDMI 2.1 device. Without this support, Steam Machine users would need to install Windows to use HDMI 2.1.

It is possible that Valve has worked with AMD to deliver full HDMI 2.1 support in its open-source GPU drivers. After all, Valve will be a major beneficiary of these efforts. These improvements will help Valve’s Steam Machine and all future SteamOS products.

You can join the discussion on AMD’s plan to deliver full HDMI 2.1 support on its Open Linux drivers on the OC3D Forums.