orangepeel Have you tried the intel_reg command to disable dithering on Linux? I just did it recently on a live USB of Ubuntu on a T480 and it both created very visible banding and seemed to significantly improve the display (aside from the hardware PWM still being there)
The Ubuntu I tried was a 2019 era version I still had on a USB, so newer versions may have other issues. But this 2019 version of Ubuntu seems to feel close to Win10 1809 — the safe Windows version for the T480 — which is a really good sign
sudo intel_reg write 70030 0x40
You might need to run sudo apt install intel-gpu-tools
first
BTW, I am so grateful this command exists today, for years I thought ditherig.exe would not be easy to "port" to Linux but all it takes is this command, and a script to re-run it on resume from sleep and monitor reconnect events
Also since you have a ThinkPad, you should definitely consider trying different LCDs via panel swapping, as sometimes even if the software is resolved there can still be an issue with the panel
My T480 was terrible on both Win10 22H2 and Win11 23H2, these OS versions had unique software and rendering-related issues such as a really intense pseudo-3D effect to everything and a general "my depth perception and ability to determine relative proportion and scale is REALLY being messed with" feeling — very similar to MacBooks
However, after downgrading to a Win10 1809 clean install, these kinds of issues noticeably "stopped" in an obvious way. Now I have a clean image that looks "correct", it doesn't feel "MacBook bad" at all anymore, but it's still straining my eyes a lot if I use it for too long
Fortunately, now I can easily tell that the "remaining" strain on 1809 is very likely coming from specifically the panel's really bad and detectable hardware PWM, that still exists even after the software fixes LOL
It was OS related, because driver issues were already ruled out as a possible cause because I tested all 3 Windows versions with identical 2017-era graphics drivers. Even with the same drivers, 1809 was the only Windows version that did not cause those software issues.
It was not placebo because:
🔻
I have a folder of photos I tested on each OS that I already know "look weird on software that messes with my depth perception", and my brain processed the content and composition of those photos completely differently on the "modern" Windows versions vs. 1809.
For example, one photo I test is a building captured at a slightly exaggerated camera angle, with a tree in the foreground that is at the very edge, i.e. the tree is half out of frame and you can only see the leaves.
In real life, the tree is entirely in front of the building, but the perspective makes it look like some leaves are above the top of the building and others below.
On 22H2, it looked like it was "the leaves at the top look like they're coming from a separate extremely huge tree that is unnaturally placed behind the building, the leaves at the bottom look like they're hovering over the building, I feel very strange pain and disorientation when I try to look 'directly at' the unnaturally large leaves at the top, and I can't simultaneously focus on the top leaves and the bottom leaves at the same time" (incorrect)
On 1809, it looked like "all leaves come from a single tree I can intuitively tell should be in front of the building, with no forcefully implied 3D depth, the proportions all look fine and nothing appears too large, and it no longer causes any pain to focus my eyes on any of the leaves" (correct)
I compared the photo on each Win10 version to my safe 2012 laptop Win8.1 setup, which I know looks "correct" and appears similar to 1809. It was easy to tell that the photo "finally looked like it should" after downgrading to 1809, as I was comparing it side by side to the safe setup the whole time.
🔺