Unable to set 120 Hz on my panel?

General system Kernel, boot, graphics & hardware
1

Hello folks!
As the title says, I have some difficulties setting up the fastest frequency for my notebook screen.
Some details first hand.
I have a ThinkPad T440p rocking an IPS 120 Hz panel, I upgraded last summer to this panel.
So, first time when I installed EOS, I was able to select the 120 value from the KDE settings for display.
However, I noticed that the frequency now is set on 60Hz, and the other higher frequencies are not even greyed out, simply aren’t showed at all.

Updated the BIOS today (long due) and booted PopOS! from a USB stick. Lo and behold, I was able to senthe display at the right frequency.
What I didn’t have time to try:
Boot from a native KDE distro and check
Install EOS with Gnome and check
Run a randr command forcing the upper frequency - I assume as much that it will be possible, I may be wrong.
Anyone experienced something similar?

2

I think that the problem lies with KWin in KDE.
However, I am still to find a tutorial or guide to manage to “hack” the compositor to be able to use the 120 Hz refresh rate.
Anyone experienced this in KDE?

3

Compiz interferes with the driver’s ability to actually refresh at 120 Hz.

Did you try xrandr --rate 120 to see if it’s supported?

Turn off desktop effects or anything of that nature.

4

@Anticupidon

5

Here is some more info.

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6

I have experienced this problem. Seems a problem with KDE sometimes. I fixed it by editing:

~/.config/kwinrc

Add under last line of this header:

[Compositing]
MaxFPS=120
RefreshRate=120

Also set Vsync to Never in compositor settings. For others with this problem - you can change the 120 value to whatever your screen supports.

Note the FPS counter you enable in the settings gui maxes out at 100fps/Hz but the actual FPS will be 120fps/Hz.

1 Like