P3421W, flickering, macOS 12, USB Type-C

Question

P3421W, flickering, macOS 12, USB Type-C

I'm using P3421W for several months and time to time have very annoying flickering and strobing issues.

The issue is not permanent, e.g. if the monitor is off for some time or I adjusted something in menus, it becomes better or worse, or goes away. Pretty confusing as I bought several of P3421W for office usage. I'm using Lunar and MonitorControl, observed the issue with these apps active and controlling Display, and without. The official DDM (Dell Display Manager) is not available for macOS. DDC/CI is on and works, I can control the monitor from apps.

Flickering could be triggered randomly, for example when I switch my web browser tabs or switch between IDE windows with light and dark background

Setup:

- M1 Macbook Pro 14"

- MacOS Monterey 12.0.1

- USB Type-C cable

- Lunar \ MonitorControl apps

- Display: P3421W, firmware M2B103

I work with P3421W at home and two offices, e.g. three different P3421W displays connected to my MacBook depending on the location. The issue is affecting all of P3421W that I work with for a while. But if I plug a new P3421W (we have many of them in the office) it works fine. (at least for a while)

Dell support redirected me here as they don't provide native display drivers for macOS and I'm looking for help.

Did anybody experience a similar issue?

MacBook Pro (2020 and later)

Posted on Jan 12, 2022 6:47 PM

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Answer 1

Jan 12, 2022 7:22 PM in response to andrey_leskov

<< Dell support redirected me here as they don't provide native display drivers for macOS >>

What PC users call "display drivers" are no more than a settings file for a specific display.

Your Mac does not require a settings file because it queries the display for the display's name and capabilities, and allows you to set resolution and refresh rates based on what the DISPLAY claims it supports.

Your curved dell display is as wide as a typical "4k" display, but not as tall.

You are getting close to the limits of what is possible over a regular USB cable. I suggest you use a high-quality USB-C cable intended for Video and not longer than 1 meter in length.

Monoprice Essentials USB Type-C to Type-C 3.1 Gen 2 Cable - 10Gbps, 5A, 30AWG, Black, 1m (3.3 ft) - Product # 24285 - $18.49

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Answer 2

Jan 12, 2022 8:02 PM in response to Grant Bennet-Alder

Thanks a lot, I'll try another USB-C cable, didn't think about this.

Was sure USB-C is good enough for 4k60Hz.

Now I use dell-provided cable USB-C - USB-C with power delivery support. Also tried with HDMI cable, same behavior.

I had cases when a flickering happens in one display for an hour and nothing helps, e.g. USB-C to HDMI change, MacBook reboot, display on\off and reset. During this period I'm able to plug another P3421W into the same port using the same cable and it works fine.

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Answer 3

Jan 13, 2022 7:22 AM in response to andrey_leskov

<< I had cases when a flickering happens in one display for an hour and nothing helps, e.g. USB-C to HDMI change, MacBook reboot, display on\off and reset. During this period I'm able to plug another P3421W into the same port using the same cable and it works fine. >>

what you describe directly above sounds like a flaky display.

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P3421W, flickering, macOS 12, USB Type-C

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