Arch Linux

Nikolai5

Member

From: North West, England, UK

Registered: 2024-01-27

Posts: 288

HDMI 2.1 FRL Support in Kernel 7.4

I've not seen any discussion on this here, but I recently found out about this: https://www.phoronix.com/news/AMDGPU-HD … RL-Default

Apparently improved support for HDMI 2.1 functionality, which is great for gaming, especially if you also use your PC as a couch gaming machine on a 4K 120Hz+ TV.

So its not going to affect everyone, but it sounds good to me, and apparently is going to be enabled by default in the kernel from 7.4 onwards.

Perhaps I don't fully understand the current limitations however, as I am able to get a 4K 120Hz output from my PC to my LG C1 via HDMI, however I recall reading somewhere that it can do that but with a more restrained colour profile or something, but I don't see any ill effects. So I wonder whether I'll notice any change when the new kernel arrives. I know its more than just the resolution and refresh rate, however.

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Ryzen 7 9850X3D | AMD 7800XT | KDE Plasma

gabrielsec

Member

From: Rio De Janeiro | Brazil

Registered: 2026-10-16

Posts: 18

Re: HDMI 2.1 FRL Support in Kernel 7.4

I don't think you'll necessarily notice a difference in basic 4K@120Hz output if it's already working. The main improvement is the higher HDMI bandwidth provided by FRL, along with VRR/FreeSync and ALLM support coming with the AMDGPU updates planned for Linux 7.4.

If your current setup uses chroma subsampling or a reduced color depth to achieve 4K@120Hz, the new support could allow a better signal format, depending on your GPU and TV. The ArchWiki AMDGPU page documents the existing HDMI limitations, while this report on the Linux 7.4 changes covers the new FRL, VRR, and ALLM support.

I'd be more interested in whether VRR works properly and whether I can use full chroma and color depth than in seeing a change to the resolution or refresh rate alone.

Regards, 
Gabriel

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