Linux - investigating eye strain problem

DisplaysShouldNotBeTVs this is great information! I'm so glad that my theories have some kind of basis I mean you can read and read about anecdotal evidence but after trying all of these different OSes on 10+ different laptops (and my own PC with external monitors), it surely has to be both a GPU "just doing the dithering anyway" or at the OS "just doing the dithering anyway" even after "disabling it" - I remember early on when I was only focused on laptops, I thought it was just a PWM thing but after many laptops that were shown to have "no PWM", I thought that maybe it was the fact that it was an integrated GPU that might have been doing weird stuff with signal. After trying laptops with both integrated GPU AND an "external" GPU like Nvidia and many failed attempts at using Windows 11 on those laptops, that's when I tried Windows 11 on my desktop PC with the same exact problems with eyestrain.

As I'm still a bit new to this, when it comes to the specifics of the intel drivers, I don't believe my desktop PC has any Intel specific components, though I do have my AMD Ryzen processor and my Nvidia GeForce 3080 TI. After looking at this particular link that you linked: https://www.mail-archive.com/intel-gfx@lists.freedesktop.org/msg253558.html

^ Is there a way to completely disable all dithering at the GPU or driver level via command line? Also, is it possible that true 8 or 10 bit displays would make the dithering unnecessary or do you think the dithering would just happen anyway? I'd love to find some more information about the implications of the future of this kind of technology because if just "doing the simple things" like watching videos in a web browser require beefier and beefier hardware or even to just play a game, then is it inevitable that this dithering will be everywhere as well?

And fyi, while using the nouveau drivers, I ran this command:

xrandr --output DP-3 --set "dithering mode" "off"

^ When I check xrandr --prop it appears that the dithering mode was switched from auto to off - Would this be the correct way to disable dithering at the GPU level even though it's targeting the monitor?

whystrainwhy Also, is it possible that true 8 or 10 bit displays would make the dithering unnecessary or do you think the dithering would just happen anyway?

Unfortunately there are still "reasons" to dither even if the desktop and monitor have the exact same bit depth - mainly color calibration.

An 8 bit desktop has 256 shades of each RGB component, but if a calibration is applied e.g. to apply "night shift" settings, gamma correction, automatic contrast enhancement, displaying sRGB gamut content "mapped within" a P3 gamut environment, LCD panel uniformity compensation and such… suddenly, you can't directly display all 256 shades of gray anymore because the color range is being "crushed" by the calibration.

The calibration will result in a ton of colors getting mapped to floating point values instead of whole numbers, meaning that "just rounding them up" would cause some form of subtle banding, no matter how high the bit depth.

GPU companies are wanting to eliminate banding whenever they can in order to make images look "smoother" so dithering is applied to "fake" these in-between shades of colors. Because even if you have 8 bit content connected to a true 8 bit monitor, there's going to be enough layers of calibration between the desktop and the output that a 1-to-1 mapping isn't possible without either rounding up/down (banding) or dithering.

The push for HDR makes all of this even worse, because the goal of HDR is to represent even more colors, such as a shade of white that's "brighter than typical pure white". All of the math required to map pretty much the "totally arbitrary and relative floating-point shades of colors" that HDR requires into even a 10 bit output while still remaining able to "eliminate" banding = dithering everywhere

This can still all be avoided by simply rounding up/down instead of dithering, but GPU companies don't want to do that as it would make their image "quality" and color "accuracy" look "worse" compared to competitors.

Today, they just throw dithering on everything as a catch-all "solution" - even when the banding would be slight enough to the point where no one aside from tech reviewers and the film/photography/publishing sector (AKA professions where color "accuracy" is important above all else and text clarity and readability do not matter as much) would care.

This is also why expensive "Pro"/artist/studio-branded products are even worse in regards to text clarity, eye strain, and ability to clearly present information-dense UI and content, compared to cheaper and "less color accurate" products.

simplex old PC's have only monitor's FRC issue

yup, plus on e.g. Windows XP/Vista/7 and PowerPC-era OS X, you actually had an easily accessible option for true 6-bit "thousands of colors" mode — meaning it used to be possible to generate a signal that was able to avoid activating FRC on some older monitors entirely.

On the Windows side the "thousands of colors" option was removed with Windows 8. Since then, any old CCFL that used to only activate FRC dithering only when receiving an 8-bit signal is now essentially forced to apply FRC at all times.

If I think all the way back to the Windows XP I'm almost certain that I used to have the thousands of colors mode selected in display properties. I actually remember having some sort of vague preference for it (instead of using millions of colors) even back then.

I still own the same Windows XP era monitor and of course, nowadays… I can see it apply its own internal "checkerboard-style" FRC whenever its fed a modern 8-bit DVI signal even if connected to a GPU that doesn't dither.

I had burning eyes and eye pain (mostly on my left eye) I also had headaches concentrated around the left eye.

These symptoms always happened while using Linux, but not windows 10/11 on the same exact hardware.

I was using LED IPS monitors (BenQ GW2485TC) for a couple of years. I kept dual booting Linux (Ubuntu, Mint, Pop OS!, Fedora, Arch, Manjaro). Arch/XFCE worked best out of all distros, but still not as good as Windows.

The first couple of days with the new qd-oled monitor I still had the same mild symptoms, to the point where I thought it wouldn’t work for me and I was going to have to return it. But the following day, the symptoms were gone and I can use it for extended sessions comfortably. I’ve only had it for about a week now though, and I’m hoping the symptoms won’t return.

I switched from LED IPS FHD to QD-OLED UHD. I’m now wondering if a good quality IPS (maybe UHD or 4K) may also solve this problem.

jaymdev

Your new monitor may have a true 10-bit panel. According to the Linux kernel code, some graphics cards have limit at 10-bit, and at this limit, dithering is not used. However, this may not apply to your situation, as it all depends on the driver and the model of the graphics card.

I am using Linux Mint Cinnamon 22.1 with the default 6.8 kernel and a custom 6.10 kernel. The issues only occur on some 6bit+FRC displays, but when using a true 8-bit display, the image does not strain the eyes even after 10+ hours of use per day.

However, I only have access to an Arc A770, UHD 630, and UHD Xe. I do not have any Nvidia or AMD graphics cards.