TECH NEWS – It’s hard to believe, but HDMI 2.1 support has been missing from Linux on AMD GPUs until now.
However, it seems that HDMI 2.1 support is finally coming to Linux, as AMD has submitted new Fixed Rate Link, FRL, patches for the AMDGPU driver. This was one of the longest-standing limitations affecting Radeon GPUs running on the platform. For years, restrictions tied to the HDMI Forum‘s guidelines, the organization behind the HDMI standard, hindered the implementation of HDMI 2.1 upstream. The new update introduces HDMI 2.1 FRL support to the AMDGPU driver, serving as a key upgrade for transmitting data to modern displays with high resolutions and refresh rates. The implementation has passed several HDMI compatibility tests, and full validation is underway. However, this release does not include the full HDMI 2.1 feature set, as capabilities such as DSC, Display Stream Compression, are still under development.
“This patch series adds HDMI FRL support to the AMDGPU display driver. DSC is still being tested and will be released later. This work has passed a representative subset of HDMI compliance tests, and a full compliance run on this branch is in progress. We don’t expect the full run to reveal any errors, as it has passed in other environments. Thanks to Siqueira, who prepared this work a couple of years ago but unfortunately didn’t manage to send it while he was still working at AMD. Thanks also to Jerry, who has been improving the Linux code and running the compliance tests. The first patch in the series isn’t related to HDMI 2.1, but it is included here because it moved some key pieces of HDMI 2.1 code around too much. It will land with the next DC patch series,” the submission reads.
This update does not include other gaming-oriented features, such as VRR, Variable Refresh Rate, or other optional HDMI 2.1 enhancements. However, the inclusion of FRL is a significant achievement, as it provides a higher bandwidth than the HDMI 2.0 standard. Previously, AMD’s open-source Linux driver did not support HDMI 2.1 due to licensing restrictions imposed by the HDMI Forum. After ongoing negotiations, AMD has finally succeeded, though Valve also deserves credit for actively participating in the negotiations.
Thanks to Valve and community developers, the HDMI 2.1 standard was integrated into the development process. This is especially important since Valve’s Linux-based gaming platforms increasingly rely on modern HDMI 2.1 display support. The HDMI 2.1 standard is particularly useful for gamers because it increases bandwidth significantly and supports formats such as 4K@120Hz and 8K@60Hz.
The interface also supports VRR and DSC; however, it may take some time before these features are fully functional on Linux.
