Wayland windows can apparently vsync to multiple monitors at once at different refresh rates
Neat little thing I just noticed, might be known but I never head of it before: apparently, a Wayland window can vsync to at least 3 monitors with different refresh rates at the same time.
I have 3 monitors, at 60 Hz, 144 Hz, and 60 Hz from left to right. I was using glxgears to test something, and noticed when I put the window between the monitors, it'll sync to a weird refresh rate of about 193 fps. I stretched it to span all 3 monitors, and it locked at about 243 fps. It seems to oscillate between 242.5 and 243.5 gradually back and forth. So apparently, it's mixing the vsync signals together and ensuring every monitor's got a fresh frame while sharing frames when the vsyncs line up.
I knew Wayland was big on "every frame is perfect", but I didn't expect that to work even across 3 monitors at once! We've come a long, long way in the graphics stack. I expected it to sync to the 144Hz monitor and just tear or hiccup on the other ones.
This setup isn't what I use, i had wanted to try as many monitors that i had ports for and this was one result that worked.
2 Sharp 18" tv's at 60Hz, different models and one can't do higher than 1280x720p so it was scaled 125%
LG ultrawide 34" 100hz
Asus 27" 75Hz
Samsung 42" tv scaled to 75% but I couldn't get its refresh rate to change. it's supposed to do 120Hz but i only get 60 Hz
since switching to wayland, i rarely have monitor problems and i love it, especially after switching to an AMD GPU. i had constant issues from my previous nvidia card.
side note, i'm super poor and all of these except the LG were given to me by friends who no longer had use for them. many of these friends do website design and ask me how their sites look occasionally. they can emulate different screens i think but they're probably trying to show off or they know i have a huge variety of screens i can test things with. I have at least 6 other monitors from 4 different brands in 3 sizes and 3 different native resolutions with 2 that do rates other than 60Hz. two are CRT's. now i'm probably trying to show off.