Laptop Screen Glitching at 120 Hz Refresh Rate

Hello all,

Yesterday I installed Fedora 40 on my new laptop and I noticed some minor screen glitches on sudden screen movements / changes, only when my screen is set to 120 Hz refresh rate. Here you can see in the picture below:

The interesting things about this bug are:

  1. It only appears when my screen is set to 120 Hz
  2. It happens both on Wayland and Xorg (less frequent on Xorg I would say)
  3. It happens both on Gnome and KDE
  4. It happens on multiple distros (tested Ubuntu as well)

Hardware Information:

  • Laptop model: Lenovo IdeaPad Pro 5 14AHP9
  • CPU: AMD Ryzen 7 8845HS
  • iGPU: AMD Radeon 780M
  • Screen: 16:10 | 2.8K | 120 Hz

Software Information:

  • OS name: Fedora Linux 40 (Workstation Edition)
  • Kernel version: Linux 6.9.9-200.fc40.x86_64

If you have any idea on how I could fix this, I would greatly appreciate that.

P.S: I’m not sure if this bug is related to the Fedora project, however since the fact that Fedora is my daily driver distro, I decided to post this here. If I should post it somewhere else, I ask you to kindly inform me about it.

Welcome to :fedora:

Would you care to try the experimental feature of VRR on Gnome desktop? It actually solved some issues for me.

gsettings set org.gnome.mutter experimental-features "['variable-refresh-rate']"

Log out or restart for it to take effect.

I just tried it out and unfortunately nothing changed.

After a deeper research, I found a workaround on the AMD GPU community reported issues repository in this thread.

To some things up, you can solve this by adding amdgpu.dcdebugmask=0x10 to the kernel parameter. To do that, follow the steps:

  1. sudo nano /etc/default/grub # Open the grub config file
  2. Append amdgpu.dcdebugmask=0x10 to the string literal on the GRUB_CMDLINE_LINUX line
  3. sudo grub2-mkconfig -o /boot/efi/EFI/fedora/grub.cfg # Update grub with the new configs
  4. Reboot your machine

To draw more attention to this issue and get it fixed as soon as possible, I kindly ask you to give this issue a thumbs up on the AMD repository.

Warning: by disabling panel self refresh, you are likely to increase machine’s power consumption.

It’s definitely a workaround, as it will tank your battery life.

Just sharing my experience and confirming that this is not related to fedora. In my case the artifacts were rare until the laptop went to sleep. After waking up from sleep they were constant whenever there was any animation running on the screen.

Also confirming that turning off panel self refresh (adding amdgpu.dcdebugmask=0x10 to the kernel parameter) fixed this for me (at least I haven’t seen any glitches since when before they were guaranteed to happen after wake from sleep).

my hw-probe: HW probe of Lenovo ThinkPad T14 Gen 5 2... #0f630f3be3

monitor: LCD Monitor SDC419F 2880x1800 302x189mm 14.0-inch (samsung)

here’s how bad it looked:

Saved my day, Thank you!