Arch Linux

simone_s

Member

Registered: 2023-11-24

Posts: 2

Gnome Wayland not running at 100Hz (multi-monitor)

Hi,
I'm encountering a strange issue with my setup, which can be summarized as:
- integrated AMD GPU (CPU: Ryzen 7 5700U)
- laptop monitor is 1920x1080@60Hz
- external monitor is 1920x1080@100Hz
- always using Wayland

Hz are measured both visually and using the integrated tool in the external monitor which shows this information.

Steps:
- boot the computer
- from GDM, login using Gnome on Wayland
- both monitors are at 60Hz now
- running

gnome-randr modify HDMI-1 -m 1920x1080@99.999

makes the external monitor blank for a few seconds, then it goes back to 60Hz

But, here it is a strange situation where it works fine (but it's pretty crazy to use as an effective workaround):
- from GDM, at boot, login using Plasma on Wayland
- set the refresh rate of the external monitor to 100Hz using

kscreen-doctor output.HDMI-1.mode.1

, where mode 1 corresponds to 1920x1080 with 100Hz
- logout
- login again but using Gnome on Wayland
- both monitors are at 60Hz, but running

gnome-randr modify HDMI-1 -m 1920x1080@99.999

works and the external successfully runs at 100Hz!

Even more interesting is the fact that, once it works at 100Hz, if I "reboot" using

systemctl soft-reboot

keeps working at 100Hz without going back to Plasma.
Re-doing the steps on Plasma is however required if I perform a full reboot.

Any ideas why such strange behaviour?

Thanks a lot!

jojo06

Member

Registered: 2023-11-04

Posts: 388

Re: Gnome Wayland not running at 100Hz (multi-monitor)

I hope there will be a solution to my problem. The 1920x1080 resolution that worked until yesterday is not working now. I deleted the user, reinstalled sway and the output command doesn't work. I think the cause of the problem is the same. There is a config setting for nouveau, one for nvidia, one for sway/gdm/gnome, one for each. In /etc/gdm they set the output resolution and monitor of course. But my problem is, there is no gdm Do i need to ?

In internet i saw people using plasme-gdm-gnome and sway at the same time. I didnt get it. I still have the xorg files and sddm, lightdm. Even though I deleted it, it's still in /etc. I don't understand

EDIT:
Found this command:

fbset -g 1280 800 1280 800 32

in https://bbs.archlinux.org/viewtopic.php?id=119015

and what about your output ? Mine output broken now it sees "unknown" the monitor. No HDMI-D-1 like yesterday. And 1920x1080 not listed in the avaible mods. Might be the problem.

Last edited by jojo06 (2023-11-24 17:51:39)

simone_s

Member

Registered: 2023-11-24

Posts: 2

Re: Gnome Wayland not running at 100Hz (multi-monitor)

@jojo06
Thanks for the response. At the end, I have reported the issue in the Mutter GitLab repo and a developer told me it may be an issue with amdgpu and I should report it to amd/drm repo (which I did).
In fact, he was right because later on I've found that no issues are present in the LTS kernel.