1 Rookie
•
3 Posts
0
2577
November 11th, 2022 05:00
U4021QW, MacBook Pro M1, flickering FIXED
Since a few days I now experience extreme flickering on my U4021QW which basically makes using the U4021QW a pain. I can get rid of the flickering if I manually lower Brightness and Contrast using DDM to about 10/25 which makes the U4021QW basically useless.
I have the following setup in place. Nothing in the hardware setup has changed since I bought the U4021QW about 8 months ago:
- MacBook Pro 13 M1, 2020
- macOS Monterey 12.6
- OWC Thunderbolt 3 Dock
- U4021QW firmware M2T104
The U4021QW is connected via the Thunderbolt 3 dock. But the flickering persists even if a connect the MacBook directly and reboot everything again. It seems like there may be something odd with the backlighting of the U4021QW?
What to do?
No Events found!
nabossha78
1 Rookie
•
3 Posts
0
November 13th, 2022 04:00
It seems that the problem was macOS outputting YCbCr instead of the correct RGB. In the OSD Menu under Color- Input Color Format, my U4021QW showed "YCbCr" instead of "RGB".
I searched around and found other macOS users had the same problem. I was able to solve it by installing and running this script.
DELL-Chris M
Community Manager
•
56.9K Posts
•
232.1K Points
0
November 13th, 2022 06:00
Good fix.
So is the speculation that the macOS had done some update which created the flickering issue?
Instead of running that script, could you have gone into the U4021QW OSD Menu- Color- Input Color Format and just manually switched it to RGB from YPbPr?
Or was the macOS not allowing this switch?
nabossha78
1 Rookie
•
3 Posts
0
November 13th, 2022 07:00
I definitely had no MacOS updates for several weeks when the issue started to come up, i am very conservative when it comes to updating critical stuff.
setting the monitor to "RGB" via onscreen menu resulted in a very weird colored output, like using a heavy yellow/red filter (completely unusable). I tried several reboots and disconnecting everything in between..., no success.
It seems MacOS should recognize the monitors color-modes by itself as there is no way to set a dedicated color-output in the system-settings despite the aforementioned script.
the culprit seems that MacOS not always generates a correct / fully parametrized .plist-file (com.apple.windowserver.displays.plist). If the file lacks information about PixelEncoding for your monitor, then the output could most likely be YCbCr instead of RGB.