M2 Mac Mini - USBC to DisplayPort - No signal - (Apple Engineer escalation)

[-BigMac-]

Hi guys.

Bit of a story.. but it's kind of a big deal 😎

I have found an issue in MacOS and/or Apple advertising.


I recently bought a Mac Mini M2, and am plugging it into my 4k monitor (144Hz).

The Apple Website states the M2 Mac Mini supports "Native Displayport output via USB-C".



An Apple support document states to connect a Displayport monitor to the M2 Mac Mini, you should do so using a USB-C to Displayport adapter cable: https://support.apple.com/en-au/guide/mac-mini/apd8e4fbbb97/mac

OK SO....

I have done just that (USB-C to DisplayPort cable). And no signal. I changed inputs from DP1.4 to 1.2, I used the other USB-C port etc etc. No signal (HDMI works fine btw, but its bandwidth limited at 60Hz).

So I tried using the USB-C to DisplayPort cable on my mums M1 Macbook Air. AND IT WORKED 😮 Full res, high refresh rate.. Hmmm

I contacted Apple Support, who went through the troubleshotting and thought it was odd too.. so I get sent off to an Apple store.

SO..

Apple Specialist confirmed
1) Apple does state USB-C to Native Displayport support on their website, and I am connecting it right.
2) My Mac Mini M2 isn't showing signal via the USB-C to DisplayPort cable to their own monitor.
3) My USB-C to Displayport cable is working fine.
4) Their M2 Macbook Pro DOESN'T display signal via USBC-DP to their own monitor
5) Their M1 Macbook DOES.

BOOM. GOTTEM

It appears, although Apple stated their M2 machines support USB-C to Displayport output -seemingly they don't. Not on the current MacOS version at least. Meanwhile M1 Machines DO.

After finding this out, the Apple Specialist told me to escalate the matter to an Apple Engineer via Apple Support.
I am awaiting a response from the Apple Engineers next thursday.

The Apple Specialist and Apple Support Escalation manager stated that it appears to be either a software issue (MacOS related) or a silicon limitation. Either way - it shouldn't be advertised on the website and support documents, until it is fully functioning 😏

Anyone here using USB-C to DisplayPort on their M2 machines? Working? Issues? OS Version?

Will update thread when I hear back from the Engineer 😬

 

[Fishrrman]

What display do you have?
What OTHER connection ports are on it? (other than displayport)

 

[-BigMac-]

What display do you have?
What OTHER connection ports are on it? (other than displayport)

Asus PG32UQ, its about $1800 AUD at the moment.

32” 4k, 144hz, Quantum Dot IPS.

It has HDMI 2.1 and Displayport.

The M2 Mac Mini only has HDMI 2.0 so its capped at 60hz, hence the need for the usbc-dp

 

[Fishrrman]

I would try a different "USBc to displayport" cable first.

If that doesn't work, I might settle for an HDMI-->HDMI connection. Even if it only runs at 60hz.

A display that is usable (even at 60hz) is better than one that is not.

 

[-BigMac-]

I would try a different "USBc to displayport" cable first.

If that doesn't work, I might settle for an HDMI-->HDMI connection. Even if it only runs at 60hz.

A display that is usable (even at 60hz) is better than one that is not.

Yea I considered that, although this works fine with 4 other machines.. maybe the M2 doesn't like this particular one? A bit weird if so

I'm using the HDMI for now, and will be returning the Mac Mini early next week, either for the M2 Pro version (Supports 240hz 4k via HDMI) or something different all together

So many viewers to this thread, yet is there not one single person running an M2 machine via USB-c to DP? :O

 

[leifp]

Ignoramus here (I have hooked up M1 mini, M1Max MBPro, and M2Pro mini to DP monitors so not relevant) and I assume you’ve tried attaching it to different ports, in case the port you’re using is defective in some fashion?

 

[-BigMac-]

Ignoramus here (I have hooked up M1 mini, M1Max MBPro, and M2Pro mini to DP monitors so not relevant) and I assume you’ve tried attaching it to different ports, in case the port you’re using is defective in some fashion?

Youve hooked those up via usb-c to DP and they all worked?

 

[alfmoonspace]

I’m running a Mac mini m2 4k monitor using a USB-C to DP. Works perfectly. Also tried using my Mac Studio with the same setup, worked great. UGREEN cable.

EDIT: Here is the link to the cable, at least in the US.

 

[djc6]

I use a USB-C to DisplayPort on my M2 Macbook Pro, but the display and cable are only rated 60Hz. Its a passive, USB-C alt-mode displayport 1.2 cable, no electronics inside of it:

StarTech.com 6ft/1.8m USB C to DisplayPort 1.2 Cable 4K 60Hz - USB-C to DP Adapter HBR2 - USB Type-C DP Alt Mode to DP Monitor Video Cable (CDP2DPMM6B) - Limited stock, see similar item CDP2DP2MBD

This USB C to DisplayPort video cable lets you connect your Thunderbolt 3 or USB Type C enabled device to a 4K DisplayPort monitor or display with just one cable, providing you with a convenient, clutter-free solution. Astonishing Picture Quality The USB C to DP adapter cable lets you harness the...

www.amazon.com

Does M2 mac-mini support USB-C DisplayPort 1.4 alt-mode?

While the StarTech.com cable works, I'm a big fan of Cable Matters cables for active cables because they offer good support and are only manufacturer I've seen offer firmware updates on their websites for display cables. For example, I just did a firmware update on a usb-c to hdmi 2.0 active cable that has a chip inside cable to fix an issue I was having. Only downside was I needed a had to have a friend do it since the firmware software requires windows. I know not to try VMs for firmware updates after bricking a couple devices.

Here is a USB to DisplayPort 1.4 cable that advertises 144Mhz @ 4K:

Premium Braided USB C to DisplayPort 1.4 Cable

USB-C to DisplayPort Cable is specifically designed to connect the new release computers with USB-C, USB4, Thunderbolt 4, or Thunderbolt 3 to monitors with DisplayPort

www.cablematters.com

My 2018 mac mini and my dad's m2 mac mini are very picky about what cables. Lots of wake/sleep issues without a cable they like. What make/model cable do you have?

 

[Chuckeee]

Hi guys.

Bit of a story.. but it's kind of a big deal 😎

I have found an issue in MacOS and/or Apple advertising.


I recently bought a Mac Mini M2, and am plugging it into my 4k monitor (144Hz).

The Apple Website states the M2 Mac Mini supports "Native Displayport output via USB-C".

View attachment 2328133

An Apple support document states to connect a Displayport monitor to the M2 Mac Mini, you should do so using a USB-C to Displayport adapter cable: https://support.apple.com/en-au/guide/mac-mini/apd8e4fbbb97/mac

OK SO....

I have done just that (USB-C to DisplayPort cable). And no signal. I changed inputs from DP1.4 to 1.2, I used the other USB-C port etc etc. No signal (HDMI works fine btw, but its bandwidth limited at 60Hz).

So I tried using the USB-C to DisplayPort cable on my mums M1 Macbook Air. AND IT WORKED 😮 Full res, high refresh rate.. Hmmm

I contacted Apple Support, who went through the troubleshotting and thought it was odd too.. so I get sent off to an Apple store.

SO..

Apple Specialist confirmed
1) Apple does state USB-C to Native Displayport support on their website, and I am connecting it right.
2) My Mac Mini M2 isn't showing signal via the USB-C to DisplayPort cable to their own monitor.
3) My USB-C to Displayport cable is working fine.
4) Their M2 Macbook Pro DOESN'T display signal via USBC-DP to their own monitor
5) Their M1 Macbook DOES.

BOOM. GOTTEM

It appears, although Apple stated their M2 machines support USB-C to Displayport output -seemingly they don't. Not on the current MacOS version at least. Meanwhile M1 Machines DO.

After finding this out, the Apple Specialist told me to escalate the matter to an Apple Engineer via Apple Support.
I am awaiting a response from the Apple Engineers next thursday.

The Apple Specialist and Apple Support Escalation manager stated that it appears to be either a software issue (MacOS related) or a silicon limitation. Either way - it shouldn't be advertised on the website and support documents, until it is fully functioning 😏

Anyone here using USB-C to DisplayPort on their M2 machines? Working? Issues? OS Version?

Will update thread when I hear back from the Engineer 😬

Could it be a defect associated just with your M2 Mac mini? Not a general design defect but a manufacturing fault with your specific unit?

 

[leifp]

Youve hooked those up via usb-c to DP and they all worked?

I did.

 

[-BigMac-]

Could it be a defect associated just with your M2 Mac mini? Not a general design defect but a manufacturing fault with your specific unit?

I mean it could be, but we did test a M2 Macbook Pro also which didn't show signal with the same cable

 

[-BigMac-]

I use a USB-C to DisplayPort on my M2 Macbook Pro, but the display and cable are only rated 60Hz. Its a passive, USB-C alt-mode displayport 1.2 cable, no electronics inside of it:

StarTech.com 6ft/1.8m USB C to DisplayPort 1.2 Cable 4K 60Hz - USB-C to DP Adapter HBR2 - USB Type-C DP Alt Mode to DP Monitor Video Cable (CDP2DPMM6B) - Limited stock, see similar item CDP2DP2MBD

This USB C to DisplayPort video cable lets you connect your Thunderbolt 3 or USB Type C enabled device to a 4K DisplayPort monitor or display with just one cable, providing you with a convenient, clutter-free solution. Astonishing Picture Quality The USB C to DP adapter cable lets you harness the...

www.amazon.com

Does M2 mac-mini support USB-C DisplayPort 1.4 alt-mode?

While the StarTech.com cable works, I'm a big fan of Cable Matters cables for active cables because they offer good support and are only manufacturer I've seen offer firmware updates on their websites for display cables. For example, I just did a firmware update on a usb-c to hdmi 2.0 active cable that has a chip inside cable to fix an issue I was having. Only downside was I needed a had to have a friend do it since the firmware software requires windows. I know not to try VMs for firmware updates after bricking a couple devices.

Here is a USB to DisplayPort 1.4 cable that advertises 144Mhz @ 4K:

Premium Braided USB C to DisplayPort 1.4 Cable

USB-C to DisplayPort Cable is specifically designed to connect the new release computers with USB-C, USB4, Thunderbolt 4, or Thunderbolt 3 to monitors with DisplayPort

www.cablematters.com

My 2018 mac mini and my dad's m2 mac mini are very picky about what cables. Lots of wake/sleep issues without a cable they like. What make/model cable do you have?

Thanks a lot for that response.
It seems it could be that some processors like some cables, and others dont?

Didn't realise there is any maleable way they differentiate themselves?

 

[leifp]

@-BigMac-

Unfortunately I’m nowhere near my desktop tech at the moment, and I have a terrible affliction wherein I collect dongles and adapters like rock candy, so I cannot tell you which cable(s) I have successfully used. It could well be a “make and model” situation…

 

[djc6]

Didn't realise there is any maleable way they differentiate themselves?

What brand/model of cable are you trying? That would help, knowing if its active/passive and if its active, what chipset, whats its capabilities are, etc.

 

[esou]

Hi, I tried an M2 Max MacBook Pro and M3 Max MacBook Pro with my 4k 144hz 10bit Samsung Odyssey G8 display (M2 Max had dead pixels so I returned and got the M3 Max).

The display works fine with the MacBooks over HDMI, full resolution and refresh rate.

Over two different USB-C->DP1.4 cables I can very sporadically get the display recognized (some 5 times on the M2 Max, twice exactly with the M3 Max). On M3 Max the image had artifacting and tearing. Configuring the display to use DP1.1 or 1.2 doesn't help.

The two cables work perfectly with an HP G8 notebook, no 10 bit color though, 4k 144hz 8bit (could the Mac be refusing to use 8bit color??)

I don't think signal integrity is the issue, if it were using DP1.1 should help. Maybe some detail in the DP implementation of my display makes negotiation shaky? On dmesg I can see that the Mac does actually detect USB-C connection and engages DP Alt mode, but nothing happens (I think some "AppleUVDM" fails to activate and then it gives up?).

I want to try an active USB-C to HDMI cable. Or maybe if someone has any suggestions on any hub that can get 4k120hz with an Apple Silicon Mac?

 

[antonyuy]

Hi! The same thing happens to me. I have a USB to Displayport adapter that works just fine on my Macbook Pro M1 but doesn't work at all on my Macbook Pro M2

 

[laptech]

Any update on this?

 

[esou]

I bought a third USB-C to DP cable and that one works reliably (a CableMatters one).

I guess it was spotty cables. Weird that it worked fine with my HP notebook or that using DP1.2/DP1.1 didn't help. I don't think signal integrity was the issue. Maybe the wiring was wrong somehow and that prevented my Mac from negotiating with the display? Maybe the display engines on M1 are more flexible with non-standard cabling and that's why some M1's can drive displays that M2 and M3 Macs fail to drive.

I also bought a USB-C to HDMI with the famous VMM7100 chipset and that works perfectly as well (after flashing with the custom firmware from the big thread). Only con is that I don't have VRR.

 

[FilthyMuppetInnuendo]

Does anyone have any idea what version of DisplayPort the M2 Mac mini (not M2 Pro) supports over Thunderbolt/USB-C in the first place? With an unmodified USB-C cable (and a Thunderbolt 4 cable) to my display, it randomly cuts out (video and audio, but not data; I can still type and move the cursor) for up to five seconds every 15-30 minutes, sometimes more often, and has done every single day since the day I bought it.

The M2 Mac mini is supposed to be able to push a 6k and a 5k display simultaneously, which is nearly 5x the number of pixels I’m trying to push right now (5120x1440@60). Theoretically it’s supposed to be able to handle this thing, but if Apple skimped on DisplayPort support (like they did on HDMI) maybe the M2 Mac mini only has DisplayPort 1.0 support and can’t actually handle this resolution over USB-C passthrough.

 

[leifp]

Does anyone have any idea what version of DisplayPort the M2 Mac mini (not M2 Pro) supports over Thunderbolt/USB-C in the first place? With an unmodified USB-C cable (and a Thunderbolt 4 cable) to my display, it randomly cuts out (video and audio, but not data; I can still type and move the cursor) for up to five seconds every 15-30 minutes, sometimes more often, and has done every single day since the day I bought it.

The M2 Mac mini is supposed to be able to push a 6k and a 5k display simultaneously, which is nearly 5x the number of pixels I’m trying to push right now (5120x1440@60). Theoretically it’s supposed to be able to handle this thing, but if Apple skimped on DisplayPort support (like they did on HDMI) maybe the M2 Mac mini only has DisplayPort 1.0 support and can’t actually handle this resolution over USB-C passthrough.

Clarifications required: are you driving two displays via USB-C or are you driving one of those with HDMI?

Edit: I assume that the “unmodified USB-C cable” is almost guaranteed to be the problem with your setup, since you specify the other cable as TB4 (which is required)

 

[leifp]

Regardless, here’s the relevant page from Apple: https://support.apple.com/en-us/102194

And here’s a summary for your use case:

Mac mini (2023) with M2 chip​

Mac mini (2023) with M2 chip supports up to two external displays simultaneously, based on the resolution (up to 6K) and refresh rate (up to 60Hz) of each external display.

​

Two external displays​

Supports two external displays in any one of these configurations:

• One display up to 6K at 60Hz over Thunderbolt, and one display up to 5K at 60Hz over Thunderbolt
• One display up to 6K at 60Hz over Thunderbolt, and one display up to 4K at 60Hz over HDMI

 

[pshufd]

I bought a third USB-C to DP cable and that one works reliably (a CableMatters one).

I guess it was spotty cables. Weird that it worked fine with my HP notebook or that using DP1.2/DP1.1 didn't help. I don't think signal integrity was the issue. Maybe the wiring was wrong somehow and that prevented my Mac from negotiating with the display? Maybe the display engines on M1 are more flexible with non-standard cabling and that's why some M1's can drive displays that M2 and M3 Macs fail to drive.

I also bought a USB-C to HDMI with the famous VMM7100 chipset and that works perfectly as well (after flashing with the custom firmware from the big thread). Only con is that I don't have VRR.

I had problems with my Intel Mac cables on my M1 mini and M1 Pro MacBook Pro. Usually of the monitor black screening from time to time. I bought CableMatters cables and everything worked. I was careful to match the cable to the resolution and frequency of the monitor. The Apple Silicon Macs seem to be pickier about the cables that you use than the Intel Macs.

 

[FilthyMuppetInnuendo]

Clarifications required: are you driving two displays via USB-C or are you driving one of those with HDMI?

One with USB-C. The HDMI port on the display itself can’t output the display’s native resolution. I consider this to be literally criminal behavior. But I ignore it because the Mac mini’s HDMI port also can’t output to the display’s native resolution and it wasn’t going to be a problem as long as I could use other outputs to get there. I only discovered this after the fact, since I had to use MacTracker to even IT JUST ****ING DID IT AGAIN I CAN’T TAKE IT ANYMORE see what the specs of the M2 and M2 Pro chips were. The M2 Mac mini has HDMI 2.0; the M2 Pro Mac mini has HDMI 2.1. Apparently.

Edit: I assume that the “unmodified USB-C cable” is almost guaranteed to be the problem with your setup, since you specify the other cable as TB4 (which is required)

How? Thunderbolt Macs supposedly have DisplayPort passthrough on those USB-C ports. I just don’t know what version of DisplayPort it’s supposed to be, so I don’t know if it’s “supposed” to be able to drive this display resolution. It’s the cable that came with the display when I bought it. You’d think that cable would be good enough to work with the product with which it came. Swapping to a Thunderbolt 4 cable (that I bought from Monoprice to diagnose things) does nothing to stop the problem. Are you trying to tell me that Apple demands I use a USB-C to DisplayPort adapter, plug it into the Thunderbolt port, plug a regular DisplayPort cable into it, and then that cable into the display? Even when the display itself has a USB-C port for the purpose of driving video input?

 

[genexx]

I have @ MBA M2:
the Asus 32"Monitor connected via USB-C -> DP Cable and variable Refresh Rate 48-165hz and HDR avail.

Get a quality Cable and check the Monitor for AMD FreeSync Premium Pro.

DRM is also no Problem and i get full Resolution on Safari for Prime or Netflix.