I have no idea what's causing my eye strain. I suspect it's related to screen flickering, since I see 4 vertical lines moving in this video https://www.youtube.com/watch?v=7GwHmpqz23g I used the laptop for just 2 hours in the morning at most, trying to change kernel parameters and had eye strain and nausea during all the day.  I don't have this problem with another laptop I own.  Is somone using slimbook Excalibur 16 without any issue? Do I need to add some specific kernel parameter after a clean installation, do I need to change the settings of the BIOS? Do I need to update the BIOS? Any help is apreciated. While I turn the laptop on or off, the screen is visibly flickering: in one second it flashes 4 times. I mean in one second, while the screen is black I see: high brightness low brightness, high brightness low brightness, high brightness low brightness, high brightness low brightness. This also happens while booting from an usb.

I forgot to mention that I get ACPI errors when I boot the system

As we discussed via email, I'll copy and paste the message so that others can see the problem and solution if they encounter the same issue.

The issue isn't with the Excalibur's screen itself, but rather with how scaling works on Linux. This could happen with any laptop that has the same resolution. Scaling in Linux still has a lot of room for improvement. Some Linux distributions, like KDE with Plasma, have made progress, but it's still not perfect.

Take a look at the following links:

https://www.reddit.com/r/linux/comments/yku0gs/scaling_on_linux_still_very_frustrating/

https://www.reddit.com/r/gnome/comments/1cjnlul/what_is_the_state_of_fractional_scaling_in_may/

https://www.reddit.com/r/gnome/comments/11ekj8o/what_is_the_state_of_fractional_scaling_on_gnome/

https://www.reddit.com/r/linux/comments/wgyugy/why_is_scaling_still_such_an_absolute_train_wreck/

Here's why the Excalibur's resolution doesn't adapt well to 150% scaling:

- 2560x1600/100%: Pixels are 1:1, native resolution, and therefore perfect, but as Frank4fun mentioned, it's too small for him.
- 2560x1600/150%: Emulated resolution of 1706.67x1066.67, the LCD pixels don't match those of the operating system/applications, so they appear blurry.
- 2560x1600/200%: Emulated resolution of 1280x800. Everything looks larger, which isn't ideal.
- 2560x1600/125%: Emulated resolution of 2048x1280, this would be the most ideal as the LCD pixels correctly adjust to those of the operating system and applications, but it's still fractional scaling and not perfect.

In conclusion, the recommendation is to try using KDE Neon with a native scale of 2560x1600 165Hz and enabling fractional scaling at 125%.