Apple M3 Pro, MacBook Pro - USB-C to DisplayPort not working

Hi, friend! Mine is the 1 meter one, there was only one moment when it worked for me but for a couple of seconds, the normal thing is that it never detects it, I have sent to buy an HDMI 2.0 to test if it works for me with this one.

Hey Grant Bennet-Alder,

I have just upgraded from an M1 Pro machine to an M3 Pro.

I used to run a Samsung G9 via a 2M USB-C to DP cable fine, and it stopped working. But I also have a DisplayLink dock which I used to run another 1920x1080p monitor and peripherals.

The G9 does not work and I suspect a short cable should do the trick, I was also able to run the G9 from the dock, but it will only run at a max of 60hz.

Is this all expected behaviour and a shorter cable should resolve my issue right?

<< I used to run a Samsung G9 via a 2M USB-C to DP cable fine, and it stopped working >>

Yes that is expected behavior. you need under ONE meter of USB-C before the 'bulge' of the adapter circuitry.

Be sure to update MacOS to latest version as early Sonoma 14 had some additional issues.

<< three different monitors I use with my M3 Pro MBP. A G27QC, CQ27G2, and a G27QPF >>

help me out here -- how are these different from each other?

what is the resolution and supported interface(s) on each of these monitors.

Ok and somewhat related, once I get a working cable, would I be able to run two 1920x1080p 60hz monitors through the dock that supports two monitors and the Samsung g9 at 144hz through the direct usbc to DP cable?

All three are 1440p 165 Hz monitors. I've been using a DP 1.2 port on all of them. The first is a Gigabyte, the second is an AOC, and the third is an MSI. They are just different brands of monitors, but similar specs on all 3 of them.

dyl-kh

DisplayLink technology creates a "fake" display buffer in RAM, sends the data out over a slower interface to a stunt box with DisplayLink custom chips that put that data back onto a "legacy" interface. It is not a true "accelerated" display, and it can suffer from lagging. Just adding the DisplayLink Driver is not adequate to get a picture -- you need a DisplayLink "stunt-box" or a Dock that includes DisplayLink chips.

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It may be acceptable for a second display showing slow-to-change data such as computer program listings, stock quotes, or spreadsheets, but NOT for full motion Video, not for Video editing, and absolutely not for gaming. Mouse-tracking on that display can lag, and can make you feel queasy.

In a pinch, it may even play Internet videos (as one user put it) “without too many dropped frames".

If you are only doing program listings spreadsheets, stock quotes, and other slow to change data, DisplayLink can work for you, but requires you to make some strong compromises.

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It is really nice to know that you can use a DisplayLink display if you MUST have an additional display for some of the types of data I mentioned. But that is NOT the same as the computer supporting a second, built-in, Hardware-accelerated display.

These displays depend on DisplayLink software, and are at the whim of Apple when they make MacOS changes. There have been cases where MacOS changes completely disabled DisplayLink software, and it took some time for them to recover.

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I think the Big Surprise for a lot of Hub/Dock buyers is that they thought they were getting a "real" display, but actually got a DisplayLink "fake" Display. If you got what you expected in every case, I would not use such pejorative terms to describe DisplayLink.

That's really interesting to know, so this is dock I purchased a while ago, and use it for additional displays, so the quality concerns are a worry for me.

https://amzn.asia/d/bbO6LCv

I will purchase a shorter cable, and hopefully the issue with the G9 is resolved.

So in future, is there any way currently of running multiple hardware accelerated external displays, or is it a waiting game?

To use more than one display on one cable out of the Mac, the port, the cable, and the first device (Dock or display) must all be genuine ThunderBolt.

You can use an additional "fake" display with a DisplayLink-capable dock.

I could not believe that something what worked fine and suddenly stopped to work is related to cable. My Macbook Pro 16" M3 refused to detect DP monitors after OS upgrade to Sonoma 14.3. I was very sceptical about posts pointing to cables (It worked previously, right? :-) ). However, I decided to risk $25 and buy a cable. I picked USB-C to DP 8k@60Hz, 4k@144Hz and guess what? It started to work. The only issue now is that my docking station is almost useless (I still have keyboard and mouse plus power going through the docking station, but video I had to plug in directly.)

Why the problem surfaced after OS upgrade beats me.

[Edited by Moderator]

Cables that use USB-C for more that ONE meter (three feet) before the conversion electronics may give you problems with newer MacOS or with higher resolution displays than you are using now.

Straight HDMI-to-HDMI cables (no adapter) can be longer, but Certified Ultra rated are preferable if you decide to use HDMI.

Solution! I have a Mabook Pro with M3 chip and the USBc to DP would not connect, the computer and monitor did not recognize each other at all. However, with a USBc to HDMI (I used an adapter) it worked great. Hopefully that helps.

You may get that too work on some level, but the best fix for the issue is to keep the cable to around 1 metere in length. In the chat, you will find that is the fix for the majority of connection issues.

Guys, it is NOT about the length. It is about quality of a cable. You have to check the supported frequencies of the cable (or bandwidth). Pick one supporting 4K@144Hz / 2K@240Hz and you can have it even 10' long. Tested. I could not believe either, because before OS upgrade it worked with older cable.

I do agree the cable has to be a quality product. That being said, the Mac requires the cable to carry a signal. If it is too long, the Mac will receive an error message and NOT connect. I have quality cables that are 3ft or longer. Those will NOT work. Every single cable I have tried that is 1 - 1.5 meters in length has worked on my M1, M2, and M3 MacBook Pro.