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M1/M2 flickering, ghosting with external display [Merged]
- Thread starter aednichols
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I have the same issue with Mac Mini M1 and Dell U2720Q. Seen a couple of times with j5create DP > USB Type-C cable adapter. Flickering, vertical frequent mattress stripes, blinking ghosting windows, color bleeding in a frame around a screen center. I really think it is backlight flickering. It does not look like an image blinking itself. But I have been wondered different monitors reveal the same issue. Looks like something on hardware level. But how? 
I also have Plugable HDMI > USB Type-C cable adapter but did not have any issues with it so far. As well as I've never had issues with j5create cable and my Macbook Pro 15 2017 plus Dell P2419H/Dell U2515H.
I also have Plugable HDMI > USB Type-C cable adapter but did not have any issues with it so far. As well as I've never had issues with j5create cable and my Macbook Pro 15 2017 plus Dell P2419H/Dell U2515H.
So, I got my monitor back from repair, where they couldn't reproduce the issue.. not to my surprise, as I found out through here it was a M1 issue instead of a monitor issue the day after I had sent it in for repair..
Anyway, the issue was obviously back again after a couple hours of use. There's this video with lots of black and gray colours with which I can easily reproduce the issue.
As miric mentioned above, the flickering indeed looks like some sort of backlight issue, I also tried changing the refresh rate while it was flickering and the amount of flickering was a lot more noticable on lower refresh rates
The flickering also persisted on my windows pc monitor input, where it would slowly dissapear after about an hour of use. (together with the vertical lines and image retention)
I have now edited the plist files to force RGB output as mentioned in another thread, and haven't had any issues since.
I'll post here if the issue comes up again, but this seems like a viable workaround
Anyway, the issue was obviously back again after a couple hours of use. There's this video with lots of black and gray colours with which I can easily reproduce the issue.
As miric mentioned above, the flickering indeed looks like some sort of backlight issue, I also tried changing the refresh rate while it was flickering and the amount of flickering was a lot more noticable on lower refresh rates
The flickering also persisted on my windows pc monitor input, where it would slowly dissapear after about an hour of use. (together with the vertical lines and image retention)
I have now edited the plist files to force RGB output as mentioned in another thread, and haven't had any issues since.
I'll post here if the issue comes up again, but this seems like a viable workaround
My monitor is a bit annoying in that it doesn't actually show what mode is being pushed to it, and I've found no way of verifying from macOS.
I've made the plist modification successfully with the script, and I've also tried using a DVI adapter for the HDMI cable (not sure if that actually will change anything and I have no way of verifying due to the monitor's OSD).
What I can tell, though, is that IF the plist settings work as expected, they do not solve my problem. In dark videos and certain games I still get the issue. It's nice to hear that it at least helps some of you, though.
I've made the plist modification successfully with the script, and I've also tried using a DVI adapter for the HDMI cable (not sure if that actually will change anything and I have no way of verifying due to the monitor's OSD).
What I can tell, though, is that IF the plist settings work as expected, they do not solve my problem. In dark videos and certain games I still get the issue. It's nice to hear that it at least helps some of you, though.
Have you deleted all versions of com.apple.windowserver.displays.plist in ~/Library/Preferences/ByHost? (Library folder in your user account, and other users as well if you have multiple users). Also, don't forget to restart.
I think someone has reported that macOS 12 beta fixes this colour mode issue. If it's really bugging you, maybe you can try it out.
Having this issue too. I have a j5create USB-C to HDMI dongle that works fine with Chromebook and PC laptop at 4K on 48" LG C1 but doesn't work on MBA M1. Bought a Cable Matters one that works with MBA M1 but text is unclear and display flickers at 4K60 while it works fine on PC laptop. Does anyone have a dongle that works properly or is something flawed with M1 USB-C to HDMI implementation?
https://www.amazon.com/Cable-Matters-48Gbps-Adapter-Supporting/dp/B08MSWMXT4/
https://www.amazon.com/Cable-Matters-48Gbps-Adapter-Supporting/dp/B08MSWMXT4/
I used Plugable HDMI 2.0 male to USB-C cable adapter with Dell U2720Q and Mac Mini M1 some time ago to watch if it will solve spontaneous flickering backlight issues. Not much time because my final aim was to use DP interface (via adapter or USB-C directly) but it didn't happen with it. I bought Maxonar 1.2m Thunderbolt/USB4 cable recently to get HBR3 and it works so far. BTW I have RGB 24bit mode all the time without any plist files manipulation on Big Sur 11.4.
i only registred to say thank you lol.
i just got my m1 mini and had a lot off issues with flickering and horizontal lines. like you said its mostly on darker sites and videos. I opened one site and there was immediate horizontal lines and flickering. Then i found your post and changed to sRGB IEC61966-2.1, this solved issue immediately, i dont know how it would work with freq of issue again, but im glad with this for now.
Guy just registered to thank you for all your attempts! You people rule...
I'm not from the US but I'm travelling during the weekend and wish to buy a 4k 32" Monitor to use with my M1 MBA to avoid this annoying issue. Any monitors that have proved so far to be bulletproof against this glitch? I don't need and curve or fancy monitor as I'm not a designer or gamer.
I'm not from the US but I'm travelling during the weekend and wish to buy a 4k 32" Monitor to use with my M1 MBA to avoid this annoying issue. Any monitors that have proved so far to be bulletproof against this glitch? I don't need and curve or fancy monitor as I'm not a designer or gamer.
As I wrote in my post, if your issue can be affected by a colour profile change, I would recommend that you try changing those plists to get RGB output. I found changing the colour profile isn't a permanent fix—it just reduces the occurrence.
Be careful though. Macbook Pro M1 + Dell P2721Q. I thought I fixed it a million times now and it always creeps back!
But now it's not flickering as often for some reason. Maybe once every couple weeks and then I flip out and close the window IMMEDIATELY. Do not leave it open or it will get worse and worse until a ghost image appears even when the monitor is in test mode.
It was flickering/ghosting on certain gray images every few hours when I first got it. So I got a replacement monitor and it did the exact same thing almost immediately. At one point I went nearly 2 months without seeing it but I wasn't working as much do to covid lockdown. It's hard to say what causes this annoying issue that seems to have no permanent fix.
I wish I'd never bought it and will probably sell to a PC user.
Right? You'd think Dell would be interested in a fix at this point. But Apple and Dell have been useless. You'd think dell would at least care because there's not a lot of good midrange monitors out there.
I don't think its a Dell issue to fix. It most certainly seems a mac m1 issue. There are multiple examples in this thread itself where a number of users have experienced this problem of flickering and ghost images out of nowhere right after using their monitor with a m1 macbook. The same monitor worked flawlessly for years before the m1 macbook.
In my case I have been using an LG ultrawide that worked flawlessly for more than a year with a PC and even an intel macbook air with 0 issues and the flickering issue only happened after I started using it with the m1 air. I returned the m1 macbook and the monitor is once again working fine with no issues with a PC and intel macbook air.
Yea I might try that too. I had already exchanged the Dell and it didn't fix it. The problem is it was so hard for me to replicate so I thought it was fixed. Apple was pretty unhelpful so far too. Just the usual stuff about resetting the EEPROM. Part of what annoyed me is that Dell has 0 info about any problems but cool companies like Eizo release stuff like this (I guess that's what thousands of dollars get you!):
www.eizoglobal.com
Apple M1/M2/M3 series Chip Equipped Mac Computer and Monitor Compatibility | EIZO
EIZO is a visual technology company that manufactures high-end monitors and display solutions for business, graphics, home entertainment, healthcare, maritime, security/surveillance, ATC and defense/aerospace.
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Don’t want to speak too soon but I’ve not had an episode of flickering since I updated to macOS Monterey beta. Anyone experienced the issue issued since updating?
It's been said that the Monterey beta fixes the RGB/YPbPr issue, so I wouldn't be surprised if issues with P2721Q and M1 become resolved with macOS 12.
I am not installing the beta yet, but my issues have been resolved by the manual plist fix.
i have a base mba m1 connected to a dell s2721qs monitor via dp cable to a dell dp/type c adapter. The screen on the dell monitor flickers on and off every few seconds at 60hz and any resolution. it only works when the refresh rate is set to 30hz. Ordered a satechi 4k 60hz hdmi to usb c cable, hoping it will work. Also apparently people at dell are aware of this problem and a software update for M1 version of the Dell Display Manager is set for September 2021. Found this info in this article https://www.macworld.co.uk/news/monitors-for-m1-macs-problems-3806526/
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Thanks for the info. That's good to know. They didn't even have any mac version of a display manager for my DELL P2721Q Display (at least when I checked months ago)
UPD i've been playing around with different settings with the same display port connection. What seems to have fixed the flickering on/off issue, is to the set the resolution to 1920x1080 60hz on the external monitor, and then disconnect the dp cable from the monitor (not mba) for approx 5 sec and then reconnect it again. And magic! Still waiting for the hdmi cable to arrive and will test it with higher resolutions, because with the current set up, applying anything higher than FHD to the external monitor results in on/off flickering.
Big Sur 11.5 update seems to have fixed the unclear text, flickering images and funny colors with Cable Matters 4K120 8K30 USB-C to HDMI dongle. According to LG C1 it's outputting 2160p60 YCBCR422 8b 4L6 which seems different than before. One drawback is the display randomly dims and brightens during active use which doesn't appear to do that with my other devices.
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so the Satechi hdmi/type c 4k 60hz cable has arrived and as expected everything now works super smooth. No flickering on and off, no other artefacts. 60 hz and any resolution is now not a problem for mba m1. So i guess it comes down to buying a high quality cable. Will update if any issues arise later on