Every article tag can be clicked to get a list of all articles in that category. Every article tag also has an RSS feed! You can customize an RSS feed too!
We do often include affiliate links to earn us some pennies. See more here.

The HDMI Forum rejected AMD's open source HDMI 2.1 implementation

By - | Views: 46,301

If you were hoping at some point to see HDMI 2.1+ on Linux with AMD + Mesa, you're out of luck right now as it's simply not going to be happening.

There's been a bug report on the Mesa GitLab of "4k@120hz unavailable via HDMI 2.1" that's been open for a few years now, with lots of comments and chatter about the issue. The problem is that HDMI is a proprietary interface, whereas DisplayPort is run by the international non-profit VESA, so it's much more complicated for HDMI support.

In an update on the bug report, AMD engineer Alex Deucher commented: "The HDMI Forum has rejected our proposal unfortunately.  At this time an open source HDMI 2.1 implementation is not possible without running afoul of the HDMI Forum requirements."

So if you're on Linux, it's going to continue to be best to buy hardware that uses DisplayPort.

On the NVIDIA side though, it seems like it may not be an issue, as developer Karol Herbst wrote on Mastodon: "Even though AMD might not be able to add support for HDMI 2.1, nouveau certainly will as Nvidia's open source driver _also_ supports HDMI 2.1 so there is no reason to believe that at least some drivers can't support HDMI 2.1

It's quite backwards, but apparently having all the logic inside firmware (like Nvidia does) will probably help us implementing support for HDMI 2.1"

So perhaps in future AMD may be able to do something similar with their firmware.

Article taken from GamingOnLinux.com.
26 Likes
About the author -
author picture
I am the owner of GamingOnLinux. After discovering Linux back in the days of Mandrake in 2003, I constantly came back to check on the progress of Linux until Ubuntu appeared on the scene and it helped me to really love it. You can reach me easily by emailing GamingOnLinux directly. Find me on Mastodon.
See more from me
30 comments
Page: «2/3»
  Go to:

zany130 Feb 29
DP to hdmi adapters also work. Thats how I get 4K 120 RGB on my LG C2 (which only has a HDMI port) VRR works as well no idea if HDR would to though...
F.Ultra Feb 29
View PC info
  • Supporter
Quoting: finaldestSo I have a fantastic 55 inch gaming capable TV which I paid over £2k for so I could have all the HDMI 2.1 features and £1k for a HDMI 2.1 capable GFX card but the HDMI forum wont allow me to use said hardware because they refuse to allow AMD to release drivers.

If I had the money I would be looking at taking legal action. I am now 3k out of pocket thanks to the HDMI forum.

I use my TV for UHD4k Bluray and Gaming Consoles and all these require HDMI. This is why I chose HDMI for PC also. But now I am forced to buy a new display that used Display Port if I want to use all the HDMI 2.1 features I have already paid for.


I really wish HDMI would just Die. Sick of jumping through hoops.

Save your money, you have no legal standing and your case would be thrown out of court.
lejimster Feb 29
I eventually want to buy a 4k OLED TV, this is the first I've ever heard of trouble supporting such a standard. How ridiculous. DisplayPort isn't very common outside of monitors so that would be an extremely annoying limitation. Hopefully by the time I upgrade a work around is created.


Last edited by lejimster on 29 February 2024 at 11:28 pm UTC
maddovr Feb 29
Quoting: F.UltraSave your money, you have no legal standing and your case would be thrown out of court.
There could possibly be a case against AMD however. I'm not in the legal field of studies, but AMD is advertising HDMI 2.1 on their RX 6000 and 7000 cards even on linux when that is not the case. So maybe...
It's a real pita. And one of the reasons I had to go back to NVIDIA. I mean 4k120hz was fine with HDMI2.0 DSC I believe, but there are a lot of devices that just default to HDMI2.1 now and I aren't seeing ANY displayport alternatives on the market.

For example, capture cards, all high end, all HDMI2.1, DisplayPort 2.0 doesn't exist. Hell its hard to find a decent priced DP2.0 cable even. So on one hand open-standard is best, on the other, open-standard sucks when few support it! (for devices etc)

Like it or not, HDMI2.1 has massive backing and support. Corporations win! sadly...


Last edited by TheRiddick on 1 March 2024 at 4:20 am UTC
Marlock Mar 1
what happens if i get an amd gpu that supports hdmi 2.1, an hdmi 2.1 cable, and an hdmi 2.1 monitor and plug them together, then boot up linux?

"no signal"? black screen? or does this setup fallback to an hdmi 2.0 featureset and i'm just limited some feature or another?

what does hdmi 2.1 do that hdmi 2.0 doesn't?


Last edited by Marlock on 1 March 2024 at 10:11 am UTC
Quoting: Marlockwhat does hdmi 2.1 do that hdmi 2.0 doesn't?

For the most part HDMI2.1 is 48Gbps bandwidth so can support higher hz with HDR and all that.

However HDMI2.0 with DSC can hit 4k 120hz 10bit just fine I believe.

When I had my 7900XTX, wayland was happy setting 4k 120hz and according to display data it was 10bit, so maybe also work with HDR?
maddovr Mar 1
Quoting: Marlockwhat happens if i get an amd gpu that supports hdmi 2.1, an hdmi 2.1 cable, and an hdmi 2.1 monitor and plug them together, then boot up linux?

"no signal"? black screen? or does this setup fallback to an hdmi 2.0 featureset and i'm just limited some feature or another?

what does hdmi 2.1 do that hdmi 2.0 doesn't?
The higher bandwidth (18 vs 48Gbps), VRR (hdmi2.0 doesn't support ver, tho Nvidia and and have working code on windows to somehow support it in a hacky way, only for windows though) and DSC for going beyond the supposed limit of the bandwidth. If you use hdmi2.1 without the proper driver you'll be limited to sorta hdmi2.0 feature set.
Quoting: TheRiddick
Quoting: Marlockwhat does hdmi 2.1 do that hdmi 2.0 doesn't?

For the most part HDMI2.1 is 48Gbps bandwidth so can support higher hz with HDR and all that.

However HDMI2.0 with DSC can hit 4k 120hz 10bit just fine I believe.

When I had my 7900XTX, wayland was happy setting 4k 120hz and according to display data it was 10bit, so maybe also work with HDR?
This is very strange, DSC was implemented as part of the HDMI 2.1 spec, and the only way to get to 4k@120Hz with HDMI 2.0 is through 8-bit bit and subsampling to 4:2:0, instead of the full 4:4:4. Are you sure you're getting 10-bit and 4:4:4 subsampling?
Quoting: maddovrAre you sure you're getting 10-bit and 4:4:4 subsampling?

I don't have the card. I just checked under WAYLAND when I did and the display information app which I've forgotten the name of, said 10-bit colorspace!


Last edited by TheRiddick on 1 March 2024 at 11:02 am UTC
nenoro Mar 1
Me reads the title
me reads the only explanation from the article

QuoteThere's been a bug report on the Mesa GitLab of "4k@120hz unavailable via HDMI 2.1" that's been open for a few years now, with lots of comments and chatter about the issue. The problem is that HDMI is a proprietary interface, whereas DisplayPort is run by the international non-profit VESA, so it's much more complicated for HDMI support.

Well at least the community plays safe
While you're here, please consider supporting GamingOnLinux on:

Reward Tiers: Patreon. Plain Donations: PayPal.

This ensures all of our main content remains totally free for everyone! Patreon supporters can also remove all adverts and sponsors! Supporting us helps bring good, fresh content. Without your continued support, we simply could not continue!

You can find even more ways to support us on this dedicated page any time. If you already are, thank you!
Login / Register


Or login with...
Sign in with Steam Sign in with Google
Social logins require cookies to stay logged in.