Patches Ready For AMDGPU HDMI 2.1 Enabled By Default With Linux 7.4 With FreeSync, VRR & ALLM

Linux 7.4 is now set to reach the elusive milestone of HDMI 2.1 support for the AMDGPU kernel graphics driver. After the HDMI Forum previously rejected HDMI 2.1 for the AMDGPU open-source driver implementation going back years, earlier this year something changed -- widely speculated to be with Valve's involvement -- that HDMI 2.1 patches began appearing for the AMDGPU driver. With the upcoming Linux 7.4 cycle, the bulk of that work will now be in place and enabled by default.

At the start of May the AMDGPU HDMI 2.1 FRL patches appeared for Fixed Rate Link to support higher resolutions and refresh rates over HDMI. That was followed by word of AMD pursuing now a full HDMI 2.1 implementation for AMDGPU. HDMI 2.1 FRL for AMDGPU landed in Linux 7.2 and in the months since other HDMI 2.1 related patches for this driver were made public. For Linux 7.4 it looks like all or at least a clear majority of that work will be merged.

Sent out yesterday to DRM-Next was the newest AMDGPU feature pull request of new material for Linux 7.4. That pull included HDMI 2.1 FreeSync support, HDMI 2.1 ALLM support, and HDMI 2.1 VRR support. The HDMI Auto Low Latency Mode (ALLM) allows for a lower latency gaming experience with some monitors/TVs. The VRR and FreeSync support is wonderful to finally see in place for AMDGPU in the mainline kernel and also important for gamers.

In addition, enabling FRL for HDMI by default for Linux 7.4. The code was initially disabled by default until the Variable Refresh Rate work was ready and the like to avoid any possible user functionality regressions.

This pull request has all that magic for bringing the HDMI 2.1 support finally into place for the AMDGPU driver.

That pull also brings updates for the upcoming AMD GFX12.1 graphics engine, DCN 6 display engine, and SMU 15 IP, among other fixes and improvements.

The Linux 7.4 merge window will open up during the second half of October depending upon when Linux 7.3 stable is ready. Linux 7.4 may still squeeze in for a release around the very end of 2026 if not early January, depending upon how the v7.3 and v7.4 cycles play out in this AI-fueled busy patch world. In any event having AMDGPU HDMI 2.1 feature patches now all aligned for Linux 7.4 will be a wonderful Christmas gift for Linux enthusiasts and gamers.