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.
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.
