HDMI 2.1 for AMD Bazzite 44

Hi, congratulations on your birthday! I’m running Bazzite 44 (IMAGE: bazzite-deck TAG: testing-44.20260827). So far so good for what I do. I’m 68 yo, retired (some occasional gaming, emails, web surfing, etc.) I think your OS is great. Maybe not perfect (yet).

My question is about the HDMI 2.1 feature for AMD Graphics Cards. I have an XFX AMD Radeon RX 7900 XT [Discrete] RX-79TMBABF9 and an LG 48 Inch Class OLED B4 Series TV Model OLED48B4PUA with four HDMI ports that allegedly supports 4K 120Hz, eARC, VRR, ALLM, QMS.
Both, the Graphics Card and the TV are supposed to have support for HDMI 2.1.

I have tried to enable HDMI 2.1 since upgrading to the 44.20260820: Stable (F44.20260820) but what happens is that the display changes intermittently between the normal display and a black screen. Is this still a work in progress or am I doing something wrong? Please help. Thanks. Keep up the good work.

Hah, someone I know had that same issue. Please check that the cable is rated for 2.1.

The thing is, most older cables are rated for 8 bit color, not 10 bits. And while they can do 4k at 120hz, once you go to 10 bit color, it will start to flicker, and it only becomes stable at 60 hz.

Thank you very much Arkalim! That is exactly what is happening. Tried your settings and there is no intermittency any more. Placed an order for a Fiber Optic HDMI 2.1 cable.

Hi, I’m testing IMAGE: bazzite-deck TAG: testing-44.20260905. I received my Fiber Optic HDMI 2.1 cable and activated the tweak in Bazzite Portal and there is no intermittency in the display. How do I verify my HDMI is at 2.1?

My display settings are 3840 X 2160 (16:9) @ 120Hz, Scale 175%, Adaptive sync set to Never, 10 bits per color. Thank you very much Arkalim and thanks to the Universal Blue team for such a great OS!

To test it directly, you would need to buy an tester (Which is expense). Or use this graph.

HDMI Version Max Bandwidth Key Resolution/Refresh Limits
1.4 10.2 Gbps 4K @ 30Hz (full RGB)
2.0 18 Gbps 4K @ 60Hz (4:2:0) / 4K @ 60Hz (4:4:4 limited)
2.1 48 Gbps 4K @ 120Hz, 8K @ 60Hz

note that the (x:x:x) is representative of compression rate.

In general compression is mostly useful for solutions to cover bigger distances than an regular HDMI allows, using network cables. For an example: Showing picture in different rooms.

More info on user side checking: How to Check Your Monitor's HDMI 2.1 Signal: A Guide

Once again, Arkalim, I am most grateful for your help. I will read the Guide in your link.

Hi, just to let you know that the HDMI 2.1 cable worked. Verified the TV settings pressing the green button seven times on the LG Remote and it shows this on the corner (randomly) of the screen:

VRR Information
120.0Hz
VRR
3840 x 2160P@120
RGB 10b 4L10 HDR10

Thank you, again, Arkalim and thanks to the Universal Blue team for their dedication and hard work to make Bazzite an amazing OS!