So, I bought an RX 7600 XT, when I was still using my 10 year old TV. Recently upgraded to an LG C4, reading the news about AMD support for HDMI 2.1 on Linux, I also went looking for a DP->HDMI adapter and found one that claims to even support VRR. After a week of getting random audio cuts, suspecting the adapter was at fault, I went pure HDMI…
To my surprise, I could run at 4K 120hz with VRR and HDR. Doesn’t that require HDMI 2.1?
You’re probably running in non-RGB 4:4:4. Quick test is to have some red console text against a gray background and if the text is fuzzy with compression artifacts at the edges, then it is not 4:4:4. You can check what mode your TV is in by clicking the green button with the two dots seven times.
Thanks for the tip. It says YCbCr420. Anything I can do to improve that?
Nope, you’re running into the dreaded AMD HDMI 2.1 limitation. The situation just sucks.
I would kindly ask the HDMI forum to point me in the direction of a DP to HDMI adapter that supports VRR or FreeSync. They seem so motivated to gain more funds from royalties, surely they know how to persuade me.
Fuck those guys. I really wish LG would support DP a bit more in their products.
Here you go: https://www.amazon.com/Cable-Matters-102101-BLK-Computer-Adapter/dp/B08XFSLWQF
It’s slightly quirky, but it does work. Although I don’t use HDMI audio so maybe you’re already using the same adapter.