LG 32UL950-W + Mini M1 + Thunderbolt

[lancastor]

I connected my LG 32UL950-W to my Mac Mini M1 via a Thunderbolt cable.

When I’m not working on my Mac Mini every 15-20 minutes the display came up with a „no connection“ onscreen message. This message is light up my whole room in the night.

There is no option on my monitor to disable this „no connection“ message.

This happens only when I connect my Mac Mini via USB-C. When using HDMI the display isn‘t waking up for a few seconds. But using HDMI isn‘t a solution for me because I need the HDMI port on the monitor for a different device.

 

[lancastor]

I bought an original Apple Thunderbolt 3 USB-C cable from the Apple Online Store.

Next try is to wipe the whole SSD and re-install macOS from scratch.

 

[iab]

Are you using Microsoft Remote Desktop and let it open?

I see a similar behavior only when I do not disconnect the MS RD session.

 

[xraydoc]

I bought an original Apple Thunderbolt 3 USB-C cable from the Apple Online Store.

Next try is to wipe the whole SSD and re-install macOS from scratch.

This is not a macOS software issue - it's a monitor issue. I had the same problem with my LG 4K monitor connected via DisplayPort to my SurfaceBook 2 and Surface Dock. When the computer was asleep, the monitor would go into sleep mode for a couple minutes, wake back up, look for signal, find none, go back to sleep, wake back up, look for signal.... rinse and repeat.

Only solution was to power off the monitor or connect it via USB-C, which meant a second cable plugged in along with the Surface Dock, a less than ideal solution. I just got used to turning the monitor off instead. HDMI connection was limited to 30Hz, also a suboptimal solution.

That monitor did not do the same thing when connected to my Mac, BTW.

Certain devices for some reason just don't play nicely together.

Reinstalling macOS, I strongly suspect, will not solve your problem. Try connecting with a USB-C to DisplayPort adapter instead of direct via USB-C, presuming your monitor has a DP port. Might fix the issue.

 

[lancastor]

I tried a USB-C to DisplayPort Adapter already. It‘s the same behaviour. Only using a HDMI cable keeps the monitor perfect in sleep mode. But I cannot drive the perfect solution with HDMI.

So I always turn off the monitor for now and hoping for a firmware update from LG.

Thanks for the hint that a reinstall of macOS won‘t solve the issue (saved me a lot of work).

 

[jdb8167]

I tried a USB-C to DisplayPort Adapter already. It‘s the same behaviour. Only using a HDMI cable keeps the monitor perfect in sleep mode. But I cannot drive the perfect solution with HDMI.

So I always turn off the monitor for now and hoping for a firmware update from LG.

Thanks for the hint that a reinstall of macOS won‘t solve the issue (saved me a lot of work).

Or try a USB-C to HDMI adapter. Just make sure you get one that supports 60 Hz.

 

[xpxp2002]

I've had this issue with this same monitor model and a 2018 MBP for years. I have yet to see any update to macOS fix it, and I don't think LG has ever released a firmware update for this particular monitor. If they have, I can't figure out where to get it. None are listed on their website for this model.

 

[lancastor]

There is no firmware update for the 32UL950-W available. ?

 

[kappaknight]

This has always annoyed me, but now I know it's a thing!

I usually just disconnect my monitor from the laptop. A firmware update would be great though.

 

[ImaginaryNerve]

I've been having a similar issue with the LG 34GP83A-B, I haven't figured out what exactly is waking the device enough to trigger the monitor to come up but not actually wake the display. I have noticed that when it happens, my mouse lights up a few seconds before hand, like it registered movement.

I suspect it'll be one of those issues that'll just train me to turn my monitor on and off instead of letting it sleep. Sort of annoying, I know, but considering my 32" LG somethingorother on my Windows PC plays the Device Connect/Disconnect sound every time I turn on or wake my computer (only when connected via DisplayPort), I've just given up.

Still though, gonna slowly work on troubleshooting this. If I find the culprit, I'll let you all know.

 

[ImaginaryNerve]

So, I might've found it.

Looks like every time I get a message sent to messages, either on my iPad or my iPhone, my monitor tries to wake up. I noticed it last night but there was a moment where it turned on though I hadn't gotten any messages (I'd thought), so I chalked it up to something else.

Today, I tested it a few times. If I get a message whether messages is open, closed, or not running at all, my monitor will wake up to a black screen then I'll get the "No Signal" message, then it'll go back into standby mode. Looks like even with Messages closed (no dot under it), it still gets push notifications of messages. Which is interesting and a little different to how it works on my non-M1 devices, though to be fair none are running Big Sur. I suspect the monitor popping on might have something to do with that. Either its when a notification gets pushed to Messages or maybe when Messages checks Apple's servers.

I'm considering turning off "Wake for LAN Access" to see if that might play a role, but I...will have to do that later this evening since I run a server off my mini and don't wanna risk service interruption just yet. I do know that SMS and iMessages are definitely triggering it, not sure if other things are as well though.

 

[xpxp2002]

So, I might've found it.

Looks like every time I get a message sent to messages, either on my iPad or my iPhone, my monitor tries to wake up. I noticed it last night but there was a moment where it turned on though I hadn't gotten any messages (I'd thought), so I chalked it up to something else.

Today, I tested it a few times. If I get a message whether messages is open, closed, or not running at all, my monitor will wake up to a black screen then I'll get the "No Signal" message, then it'll go back into standby mode. Looks like even with Messages closed (no dot under it), it still gets push notifications of messages. Which is interesting and a little different to how it works on my non-M1 devices, though to be fair none are running Big Sur. I suspect the monitor popping on might have something to do with that. Either its when a notification gets pushed to Messages or maybe when Messages checks Apple's servers.

I'm considering turning off "Wake for LAN Access" to see if that might play a role, but I...will have to do that later this evening since I run a server off my mini and don't wanna risk service interruption just yet. I do know that SMS and iMessages are definitely triggering it, not sure if other things are as well though.

This is a really interesting behavior, because mine periodically wakes even when it’s not receiving a message.

I also tried setting Do Not Disturb while sleeping and turned off Power Nap, but neither seemed to make a difference.

 

[ImaginaryNerve]

Its very interesting, and it has me wondering if there's some kind of network activity in the background that might be triggering it. Like maybe the computer is checking for updates (I had a Windows PC that would turn the monitor on every time it wanted to check for updates, I think it was Windows Vista or Windows 7? It was ages ago.), or maybe something to do with the notification window on the right? I don't use it much as I hate notifications, but might be something there.

Either way, something is triggering it. Since Messages can reliably trigger it, I'm wondering what else might be doing it and if its push notifications in general or maybe a background process linked to a notification like checking mail or checking for updates, etc.

Later this evening, I'm going to disable LAN access and see if it pops up at all over the course of an hour or two. I am kind of annoyed that even when not running in the dock, Messages will still check and notify you of SMS/iMessages, as I don't remember it doing that before. Though tbf, I think the last version of macOS I used prior to the M1 was...what was the one before Catalina?---

As I was typing this, it just popped up again but this time with nothing from Messages. I DID get a notification on my phone from a weather app at the same time, though that app isn't installed on the Mini...

Curiouser and curiouser.