Screen flickering on Ubuntu

The screen flickerung is coming from Panel Self Refresh (PSR), a power saving feature used by Intel iGPUs which is known to cause flickering in some instances. A temporary solution is to disable this feature using the kernel parameter 364 i915.enable_psr=0. Here is how you can do It:

Edit the grub file:

sudo nano /etc/default/grub

and add to the end of the GRUB_CMDLINE_LINUX_DEFAULT line

i915.enable_psr=0

In the end it should look like this:

GRUB_CMDLINE_LINUX_DEFAULT="intel_iommu=on iommu=pt i915.enable_psr=0"

then run:

sudo update-grub

to apply those changes and reboot.