Support for newer HDMI features in the open-source AMD Linux graphics driver have been [1]limited due to being blocked by the HDMI Forum . There are though some new HDMI gaming features being enabled via new AMDGPU kernel driver patches that are coming outside of AMD and based on public knowledge and/or "trying things out until they work/break" for functionality like HDMI Variable Refresh Rate (VRR) and Auto Low Latency Mode.

Tomasz Pakuła has been working on these new HDMI features for the AMDGPU Linux driver. He's sent out a few different patch series recently while today sent out the latest patches and combined it into a single patch series for "HDMI Gaming Features". Pakuła sums up the work as:

- Fixes VRR not detected if monitor uses GTF flag for ranges

instead of Range Limits Only

- Detects if AMD vsdb carries a wider VRR range and uses it instead

- DP->HDMI PCON changes which includes a module property to override

PCON ID check

- Parses HDMI gaming features in generic drm

- Reintroduces proper HF-VSIF and VTEM info packets

- Adds support for Auto Low Latency Mode

- Adds support for HDMI VRR

The AMDGPU driver has long supported VRR/FreeSync with DisplayPort outputs while this gets HDMI VRR working too.

HDMI Auto Low Latency Mode is an HDMI 2.1 feature for "Game Mode" for a smoother and more responsive gaming session by helping to reduce input lag.

[2]

As for making these HDMI features work given the past troubles due to HDMI Forum restrictions, this functionality was sorted out using public information and simply trying until things worked:

"Everything in this patch series has been based on already public code/knowledge or trying things out until they work/break."

Those interested can see [3]this patch series for these HDMI Gaming Features for the AMDGPU kernel driver.

Here's to hoping the latest patch review goes well and that there won't be any concerns by AMD over upstreaming these changes into the AMDGPU Linux kernel driver.



[1] https://www.phoronix.com/news/HDMI-2.1-OSS-Rejected

[2] https://www.phoronix.com/image-viewer.php?id=2026&image=amd_hdmi_gaming_lrg

[3] https://lore.kernel.org/lkml/20260119011146.62302-1-tomasz.pakula.oficjalny@gmail.com/