For years, using HDMI to connect a PC with AMD graphics to a new TV or monitor on Linux was frustrating. Although the hardware had more than enough support for HDMI 2.1, licensing restrictions from the HDMI Forum prevented FRL (Fixed Rate Link) technology from being included in open-source drivers such as AMDGPU. This left users stuck with lower resolutions and refresh rates or forced them to depend only on DisplayPort.
This is finally changing. AMD has prepared a set of changes for the Linux 7.4 kernel that will not only enable HDMI 2.1 FRL by default, but will also add the full set of key gaming technologies such as FreeSync, VRR (Variable Refresh Rate) and ALLM (Auto Low Latency Mode).
The addition of FRL is the real driving force behind all of this. This feature replaces the old TMDS standard from HDMI 2.0 and makes it possible to use the full bandwidth of the cable. In everyday use, this means gaming at 4K and 120 Hz (or higher), with greater color depth and DSC compression without stuttering.
AMD Is Finally Fixing One of Linux Gaming’s Biggest HDMI Limitations
The improvements included in this patch solve the main problems:
- VRR and native FreeSync: The screen will match its refresh rate with the graphics card in real time. This helps remove screen tearing and flickering. AMD has also added fixes to better detect displays that support FreeSync through manufacturer data blocks.
- ALLM: When you start a game, the system can automatically tell your TV or monitor to switch to its low-latency gaming mode. You will not need to change the setting manually.
- Passive VRR: This keeps VRR ready in the background. It can help prevent the screen from going black for a moment when switching between the desktop and a game.
FRL first appeared in Linux 7.2, but it was disabled by default while these features were still being improved. Valve has also helped speed up the work because it wants better HDMI support for SteamOS and devices based on AMD hardware.
The Linux 7.4 merge window is expected to open in October. The final version of the kernel should arrive by the end of this year or early next year. This could finally remove one of the biggest HDMI limitations for gaming on Linux.
