Complementing the HDMI 2.1 Fixed Rate Link (FRL) support that AMD already upstreamed to the Linux kernel, AMD engineers have been further ironing out their HDMI 2.1 implementation for the open-source AMDGPU Linux kernel driver. The latest quest has been getting HDMI 2.1 variable rate refresh (VRR) support upstreamed along with HDMI Auto Low-Latency Mode (ALLM).

Sent out at the end of July was AMD's [1]AMD HDMI 2.1 VRR and ALLM support as part of the modern HDMI gaming features. And with that closer to completing the long elusive HDMI 2.1 support in this open-source AMD Radeon Linux graphics driver.

Sent out today was the second iteration of the HDMI VRR and ALLM patches.

"This series adds HDMI 2.1 gaming support to amdgpu: Variable Refresh Rate (VRR) derived from the HDMI Forum VSDB (HF-VSDB), and Auto Low-Latency Mode (ALLM). It builds on a drm/edid patch that parses the HF-VSDB gaming capabilities into struct drm_hdmi_info."

[2]The patches don't bring any big changes but just some minor code improvements and code restructuring over the original series. Plus the patches apply against the latest amd-staging-drm-next Git state.

So the patches appear largely in order now, but due to the timing, won't be making it for the upcoming Linux 7.3 merge window. Yesterday AMD already sent out [3]their last planned feature pull request to DRM-Next for the Linux 7.3 merge window opening up in the second half of August. But with the DRM-Next cutoff this week, they are out of time for queuing this code. But here's to hoping that this HDMI VRR and ALLM support will be ready to go with the Linux 7.4 kernel cycle at the end of the calendar year.



[1] https://www.phoronix.com/news/AMDGPU-HDMI-2.1-ALLM

[2] https://lists.freedesktop.org/archives/amd-gfx/2026-August/150041.html

[3] https://www.phoronix.com/news/AMDGPU-Linux-7.3-Last-Round