Hidden dithering or broken synchronization in graphics stack that causes eye strain?

kammerer

New Member


Messages: 7

Hi All, my question could look strange, but actually I can't use any modern FreeBSD/Linux distribution
cause of eye strain that i got on any graphic card (nvidia, ati, intel) regardless of used driver.
I'm using Ubuntu 14 now without any problem but on attempt
to switch to any newer OS on same hardware (and same monitor: Dell U2711 with CCFL backlight)
I got problem with eyes (seems problem starts with overstressed eye muscles).
Looks like that problem could be linked with software changes but It's not clear which ones.

So maybe you could suggest what is the root of problem.
Is it some hidden system dithering? Or some problem with video data synchronization?
Or smth else that could affect pixel rendering/representation/transfering that affects eye focusing
(in my case it's not linked with font rendering cause I got same problem just looking at any picture)?

xrandr output on both system is quite similar:

FreeBSD 12
2560x1440 (0x49) 241.500MHz +HSync -VSync +preferred
h: width 2560 start 2608 end 2640 total 2720 skew 0 clock 88.79KHz
v: height 1440 start 1443 end 1448 total 1481 clock 59.95Hz
1920x1200 (0x4a) 154.000MHz +HSync -VSync *current
h: width 1920 start 1968 end 2000 total 2080 skew 0 clock 74.04KHz
v: height 1200 start 1203 end 1209 total 1235 clock 59.95Hz


Ubuntu 14.04
2560x1440 (0x57) 241.5MHz +HSync -VSync +preferred
h: width 2560 start 2608 end 2640 total 2720 skew 0 clock 88.8KHz
v: height 1440 start 1443 end 1448 total 1481 clock 60.0Hz
1920x1200 (0x58) 154.0MHz +HSync -VSync *current
h: width 1920 start 1968 end 2000 total 2080 skew 0 clock 74.0KHz
v: height 1200 start 1203 end 1209 total 1235 clock 60.0Hz


Some additional context:

Maybe you now about ledstrain.org society that unites different peoples with one common problem:
they can't use monitors with led backlight. They have year-proven old hardware with CCFL backlighted monitor
but on attempt to swap it with LED backlighted one they got different problems: noursea, eye-burning, headaches and so on.
With time many of them also starts notice that they have similar eye/brain related problems with newer OS (Linux, Windows) on same year proven hardware.

NB: There was a post on forum 4 year ago "Eye strain from certain video modes/drivers"
where foster found solution for himself with disabling hardware acceleration:

"I just realized the "working" modes that I marked green in my first post have something in common.
They don't use hardware acceleration. Do you know of any differences in the video signals when hardware acceleration is used?
Even the smallest difference might matter, so please reply if you know something."

 
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