Temporal Dithering Sensitivity - My Solution
Jerry these eink phone covers are super cheap. not sure how useful they are ..
https://www.amazon.com/dp/B00LYLFRF2/Laptops probably used dithering for many years? Why is it suddenly a problem and only on new models for some people?
maybe because LED's have faster and more abrupt response times than CCFL's
Alyosha2001 context?
The backlight has ZERO to do with the dithering (unless it's an OLED), the dithering is a product of the panel and/or video card.
JTL yes, you are right. I confused it. The context was „Laptops probably used dithering for many years? Why is it suddenly a problem and only on new models for some people?”
Alyosha2001 I figured
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AGI Did you ever get an answer to your resolution question? I recall that the only LED backlit laptop I used before this was a 2011 MBP 17" antiglare and run in a reduced resolution as I just wanted things larger. I never used it in native resolution. I don't have it anymore but recently tried a 15" version on native resolution and got terrible strain.
Lowering the resolution did not solve eye strain for me on desktops. Except when the low resolution was the result of using a generic video driver (Windows: "Standard VGA", Linux: "VESA"). Keep in mind that some (most?) modern graphics cards always output the display's native resolution by default, doing all the upscaling themselves instead of letting the desktop monitor handle it. They completely bypass the desktop monitor's scaling function this way. I am not sure how this is usually done in laptops.
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hpst Nope, sorry. I was suggested on this forum that reducing the resolution may have an effect on temporal dithering and should not affect PWM, so I would tentatively rule the latter out. But I have not gone farther than that. Inquiring at manufacturers and electronics shop did not lead anywhere. I would definitely call it lack of interest, in most cases both lack of interest and knowledge. If you find something out, please let us know!
Hi All,
I have been having this led strain problems for quite sometime. The following combination seems to give a usable display (for me) on Lenovo laptops running Manjaro Linux KDE. I have done other modifications such as Xorg configurations, so this might be a cumulative effect, but this last modification gave significant improvement. So, this might of help to someone, even if they have other laptops or Linux distributions:
If you have discrete graphics, disable it and use only integrated, by selecting UMA only graphics in the BIOS. (This probably is not mandatory. Did this only to eliminate potential problems with hybrid graphics, non-intel drivers also doing modesetting etc.)
Pass the video option to the grub command line. For example: video=eDP1:1920x1080-16
Format is: dislpay:resolution-bpp
display value can be obtained by doing xrandr
The default bpp seems to be 32. 24 did not seem to reduce the strain. 16 does reduce the strain. Some monitors are truly 8-bpp, in which case this value could probably be 24. The test image at https://cdn.avsforum.com/d/de/525x525px-LL-defb4132_vbattach85246.gif at the site https://www.avsforum.com/forum/166-lcd-flat-panel-displays/874438-test-your-lcd-panel-s-dithering-technique-pictures-included.html seems to give some good guidance on this aspect
For testing this, you could press 'e' at the initial grub screen, add video=eDP1:1920x1080-16 in the arguments (typically after quiet).
For permanent, add video=eDP1:1920x1080-16 to GRUB_CMDLINE_LINUX_DEFAULT and do "update-grub" (or equivalent in your distribution).
Some pointers related to the video option:
https://ubuntuforums.org/showthread.php?t=1743535
https://wiki.archlinux.org/index.php/kernel_mode_setting
http://distro.ibiblio.org/fatdog/web/faqs/boot-options.html
From my limited understanding, it seems that Linux KMS is setting the bpp to 32 which causes dithering.
Please post your feedback, positive or otherwise.
Thank you.
Ravi
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ravipra Ravi what Lenovo laptops are you using and do you know what panels are in them? Manufacturer/IPS vs TN/PWM etc?
I have a 2014 X1 Carbon with Intel 4400 graphics, an LG 1080 IPS panel in it with no PWM and it strains me as well as any other panel I have put in it regardless of specs. It has KDE Neon installed right now. Are these changes made in the etc/default/grub file? Could you be more specific as to exactly what to put where? I am not great at linux. I have edited the above file before as some people have suggested trying dithering and driver entires there but nothing was helpful and mostly broke things.
Hi hpst, I have the following laptops:
Lenovo Z51-70 and Lenovo Ideapad 310. I will check on the panels and get back. I also got improvement on my Dell desktop with a Dell monitor (which doesn't seem to be true 8-bit). I also have couple of other monitors which claim to be true 8-bit. I will try my above solution with 24 as the bpp value and see if it gives improvement.
Please let me know any specific questions that you might have on the solution I posted. I will be more than happy to give all the details.
Ravi
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Yes, that is the right file.
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" would become
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash video=eDP1:1920x1080-16"
My output of xrandr | head
Screen 0: minimum 8 x 8, current 1920 x 1080, maximum 32767 x 32767
eDP1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 340mm x 190mm
1920x1080 60.01*+ 59.93
1680x1050 59.88
1400x1050 59.98
1600x900 60.00 59.95 59.82
1280x1024 60.02
1400x900 59.96 59.88
1280x960 60.00
1368x768 60.00 59.88 59.85 I have other optimizations also, which might be contributing to the +ve effect. If so, mine is:
GRUB_CMDLINE_LINUX_DEFAULT="quiet norandmaps nokaslr audit=0 cgroups_disable=memory video=eDP1:1920x1080-16"