So I’m running Fedora 38, as a bit of a traditionalist, installed the cinnamon spin, and again, as a bit of a conservative type, I tend to wait a bit before upgrading to the latest version. I received my FW13 AMD a couple of weeks ago, and have been using it at work, so almost exclusively hooked up to an external display. Yesterday I noticed that, when the screen is mostly dark (e.g. dark mode UI, terminal, or the boot splash screen even), the blacks of the screen appear noisy. On closer examination, the noise turned out to be random pixels (or clusters of pixels) flashing up in red, green, blue, sometimes white. Sometimes changing the resolution stops the flickering, sometimes it doesn’t. I also noticed that lowering the refresh rate at native resolution to 48hz didn’t work at all.
I’ve done some searching, but couldn’t find any known issues on lkml, or anywhere else that seemed to describe, or explain my issue. I submitted a bug report, and literally as I was typing that up, the backlight just gave out (something that I did some threads about here, but on rebooting, the shutdown splash screen restored the backlight, and it’s been back up since).
Some more digging through journalctl logs doesn’t give me any clue as to what could be going on either. Maybe I’m not looking in the right place, maybe someone else had the same issue, and managed what I couldn’t (ie fix the problem). After work, I’ll take some time, upgrading, checking logs, and report back if I managed to fix the problem.
I did notice something: the noise seems to quiet down when I have a terminal open in full screen and the CPU is idling. When opening a large-ish file in Vim, for example, the noise flares up until my LSP has loaded, and everything is set up/loaded, and then it all settles down to almost nothing again. Every time I’m doing some work, it’s quick to return, though. Even moving my cursor around causes the noise to increase significantly. Basically, it seems to related to CPU or RAM utilisation, causing some noise in the signal, perhaps?