Screen keeps modesetting on high refresh rate

seth · 2026-02-15 17:10:46

VRR is the "AMD FreeSync Premium Deluxe Extra SpecialNeeds" Option, set that OFF

CLiPPY · 2026-02-15 17:16:15

I tried it both on and off, and somehow the problem was there in both situations.
However note that when I switch it while wayland is already running the problem disappears (switching either way gives the same result), but once I log out and login again the problem is back.

Oh and I forgot to mention this, when I solve the problem by switching the mode the OSD fps counter stays solid on 180, ig this is why it disappeared.

So apparently when that spike in fps happens the screen (sometimes) modesets. But I can't figure out when that spike happens, neither when it modesets or just deals with the fps drop peacefully

CLiPPY · 2026-02-15 18:04:11

Hmmm... disconnecting the HDMI cable after loggin in in and reconnecting it makes it work. but once you log out and sign in again the problem is back.
I even tried another HDMI cable, the one that there is no way it has a problem, as it is the one powering the connection of the TV since 7 or perhaps even 8 years.
I suspect that what makes the problem disappear is making the screen successfully modeset, either by editing the configuration of the screen firmware, or by disconnecting a cable.
also that modeset that fixes it, (as I suspect) has a rule for it to work:

It should be from 180 -> 180:
so when you disconnect a cable it was already rendering 180 but when you plugged it in it is also on 180.
when you edit the configuration of the monitor that doesn't even remotly touch the fps.

So 60 -> 180 doesn't help at all:
on my login screen (sddm) I set it to 60 (bc I couldn't figure out how to make it 180hz lol, and cause I don't need frames anyway on my login manager), so when you log in you do a jump from 60 to 180.
And so is when you change Niri's config to make it 60 then 180. the last modeset that will be applied is the 60 -> 180 after all

This is definitely The hardest troubleshoot I ever did... But somehow I'm getting much dopamine when I get to discover those tiny little pieces of information here and there XD

seth · 2026-02-15 22:04:42

https://github.com/niri-wm/niri/issues/2967
https://github.com/niri-wm/niri/wiki/Co … fresh-rate

Some monitors will continuously modeset (flash black) with VRR enabled; I'm not sure if there's a way to fix it.

Make sure it's not enabled there.

CLiPPY · 2026-02-16 04:02:43

Yes it is disabled, and that is the default option.
I tried once enable it when the problem was there but that made the problem even worse and more annoying.

CLiPPY · 2026-08-30 14:01:34

@seth
I finally found the solution to this problem. XDDDD
it was that for some reason, I'm using this modeline:
```
[clippy@Battlestation:~]$ cvt 1920 1080 180
# 1920x1080 179.98 Hz (CVT) hsync: 216.33 kHz; pclk: 581.50 MHz
Modeline "1920x1080_180.00" 581.50 1920 2096 2304 2688 1080 1083 1088 1202 -hsync +vsync
```
and for some reason, all distros made this the default for me, probably it was just the driver.
so just enabling RB made it work just fine
```
[clippy@Battlestation:~]$ cvt 1920 1080 180 -r
# 1920x1080 179.88 Hz (CVT) hsync: 211.90 kHz; pclk: 440.75 MHz
Modeline "1920x1080R" 440.75 1920 1968 2000 2080 1080 1083 1088 1178 +hsync -vsync
```
which seems like what Windows was using.
here is how I did it with Niri:
```
// output "HDMI-A-1" {
// mode "1920x1080@180.003"
// }

output "HDMI-A-1" {
mode custom=true "1920x1080@179.98"
modeline 440.75 1920 1968 2000 2080 1080 1083 1088 1178 "+hsync" "-vsync"
}
```

seth · 2026-08-30 14:27:52

and for some reason, all distros made this the default for me, probably it was just the driver.

for OUT in /sys/class/drm/card*; do echo $OUT; edid-decode $OUT/edid; echo "================="; done

You'll need https://archlinux.org/packages/extra/x86_64/v4l-utils/

You can drive this lower w/ cvt1.2

# 1920x1080 @ 180.000 Hz Reduced Blank (CVT) field rate 180.000 Hz; hsync: 212.040 kHz; pclk: 424.08 MHz
Modeline "1920x1080_180.00_rb2"  424.08  1920 1928 1960 2000  1080 1164 1172 1178 +hsync -vsync

Since the stages are at 340MHz and 600MHz, https://en.wikipedia.org/wiki/HDMI#Cables it's gonna be your specific one if shifting within that range does anything.

Arch Linux

#26 2026-02-15 17:10:46

Re: Screen keeps modesetting on high refresh rate

#27 2026-02-15 17:16:15

Re: Screen keeps modesetting on high refresh rate

#28 2026-02-15 18:04:11

Re: Screen keeps modesetting on high refresh rate

#29 2026-02-15 22:04:42

Re: Screen keeps modesetting on high refresh rate

#30 2026-02-16 04:02:43

Re: Screen keeps modesetting on high refresh rate

#31 2026-08-30 14:01:34

Re: Screen keeps modesetting on high refresh rate

#32 2026-08-30 14:27:52

Re: Screen keeps modesetting on high refresh rate

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