MacBook Pro M4 with thunderbolt 5 and portable monitor

Same problem, though it DOES work if you use a usb c display hub in between the portable monitor and the thunderbolt 5 ports. No power passthrough needed.

I Have access to both a M4 pro Mac mini and an M4 Mac mini. It works perfectly without the hub on the M4 Mac mini. It doesn’t work on the M4 Pro at all unless I throw the hub in between.

The person that said don’t get distracted by thunderbolt five and that it wasn’t the issue, ngl rn it looks like 5 is the issue.

the hub I used is this one off amazon

https://a.co/d/gH16MI0

I already had that hub, I have 15 different thunderbolt cables of varying lengths, I have about 12 USB-C cables, capable of delivering display signals, also varying lengths, I have tested every single one of them and nothing works, and the one factor involved that seems to make the difference is that it is a thunderbolt five port.

every single one of my cables works with thunderbolt four on the M4 Mac mini. But again, as has been said, not a single of my 27 cables works when using the thunderbolt five ports on the M4 Pro Mac mini.

Thanks for your armchair input, but I think I will stick with hard results from my actual tests.

Though I cannot conclusively say that it is SPECIFICALLY because of thunderbolt five, I think we can all agree that something about the thunderbolt five models of the M4 Macs seem to have an issue connect connecting to portable displays and delivering signal.

Could this be a software issue? Maybe. maybe it’s a firmware thing that just needs an update. Could it be something else? Sure. But as of right now, based on every piece of evidence presented, it seems like Macs with thunderbolt five are not able to deliver a display signal along with the power to a portable display without that hub I am using or a similar one as the in between.

I get that in a perfect world, based on how things should be working in theory with thunderbolt five as you have explained in your other comments, it “shouldn’t” be an issue. But, here we are. 🤷‍♂️

lindowmac wrote:

I will say though USB4 =/= Thunderbolt 4.

Yes. This. My understanding is that

• USB4 host ports can optionally support USB4 40 Gbps transfers.
• USB4 host ports can optionally support Thunderbolt Alt Mode. While the USB4 specification is based upon Thunderbolt 3, it is also possible to implement Thunderbolt 4 or Thunderbolt 5.
• Thunderbolt 3 support does not automatically imply USB4 support. There are many Intel Macs that support Thunderbolt 3, but that predate USB4.
• Thunderbolt 4 came after Thunderbolt 3 and USB4, and Intel has attempted to use the Thunderbolt 4 specs and certification requirements to force cleanups, in the way of making once-optional features mandatory on equipment that is Thunderbolt-4-certified.

Yes, it is a different machine. But:

• If what you are saying is true....why did that same portable monitor work with the non powered USB C display hub I used as the in-between? If the issue was power as you claim, why would the NON-powered hub placed between the thunderbolt 5 port and the portable monitor make it work suddenly?
• The reality of our situation is that, regardless of how things 'should work', portable monitors that have worked on my M1 Max MBP, my brothers M2 Pro MBP, my friend's M2 Pro Mac mini, my plain M4 Mac mini....those same monitors are not working on the M4 Pro Mac mini. Nor is the portable monitor working on OP's Mac. Regardless of what is being said, there is a change in results based on the introduction of the M4 Pro featuring thunderbolt 5 ports.
• Why are you trying using numbers to support the idea that it shouldn't work on the M4 Pro Mac Mini but then speculative logic to support why it did work on the plain M4 and calling it 'lucky'? This isn't super helpful. I am trying to provide useful information based on real world results. Saying something "should" or "shouldn't" work while staring at results in the face doesn't really bring anything to the table here, nor does calling something "lucky".
• Where did you get the numbers saying the Mac mini wasn't designed to deliver a certain amount of power? I am not calling you wrong, I just don't know where you got that from. I don't see it listed in the device specs and as you pointed out, the OP's machine and the Mac mini are different machines so we can't really rely on the numbers provided in this thread.

I’ve got a similar problem, but with a M2 pro Mac mini vs a M4 pro Mac mini

Same monitors, same cables. (Thunderbolt 4 cables) Works fine with the M2 pro, Mac mini powers both monitors, but M4 pro Mac mini won’t even power one of them. 

Same problem. I had a Macbook Pro M2 Pro, used with my portable display, worked flawlessly. Got this Macbook Pro M4 Pro now, and with same display cable and same portably display, it doesn't work. Portable display states "No Signal".

Rather that fruitlessly post what cable and portable display I am using, likely shouldn't matter: it worked with my M2 Pro MBP, so I feel via backwards combatibility should work with this new M4 Pro MBP.

lindowmac wrote:

Rather that fruitlessly post what cable and portable display I am using, likely shouldn't matter: it worked with my M2 Pro MBP, so I feel via backwards combatibility should work with this new M4 Pro MBP.

Maybe the problem is that the portable monitor is being overly demanding of bus power – and that while the M2 Pro MBP was generous with handing out extra bus power, that doesn't necessarily mean that anything is wrong with the M4 Pro MBP.

Since you haven't been able to get any reports from the computer about how much power the external monitor wants to suck out of the MBP, and since you haven't told us which external monitor it is (which might lead us to specifications or manuals for that monitor, on the Web), we don't know what it's trying to do.

All we know is that you seem to want the MBP to power an external display about which there are no specifics. That's not much of a basis for troubleshooting.

My feeling is that you should assume that an external display needs its own power source (whether that is wall power, or a battery of its own) until proven that its demands are within what a notebook is willing to supply.

DougB851 wrote:

Grant I recently purchased a MB Pro 16 M4 with a Max chip. I was under the belief that Thunderbolt 5 was a standard for this configuration. However, the hardware listed on the machine delivered shows all three ports as Thunderbolt 4. Went to Apple Store to look and all of their M4 Max and Pro units also showed Thunderbolt 4.

Have you seen this elsewhere? Has anyone purchased a machine that shows a Thunderbolt 5 in the hardware overview?

Please advise. Thank you.

M4 Pro and M4 Max

• Three Thunderbolt 5 (USB-C) ports with support for:
• Charging
• DisplayPort
• Thunderbolt 5 (up to 120Gb/s)
• Thunderbolt 4 (up to 40Gb/s)
• USB 4 (up to 40Gb/s)

MagSafe 3

Thunderbolt 5

3.5 mm headphone jack

SDXC

Thunderbolt 5

HDMI

source:

MacBook Pro - Tech Specs - Apple

NB> ThunderBolt 5, as I mentioned above, is NO DIFFERENT from earlier versions of Thunderbolt. ThunderBolt-5 can ONLY provide faster speeds when talking to other genuine ThunderBolt-5 devices, of which there are essentially NONE at this writing.

Thank you. And understood about current lack of TB5 accessories. I have pre-order an external TB5 hard drive from OWC.

My disappoint is that there is nowhere in the machine’s hardware overview to see what Thunderbolt ports are installed. Similar to memory or core count. Only place is see is the read speed of 120gbs.

dragos-florin wrote:

Here's with a 145w power bank connected, both laptops testes in the same setup and work as expected , monitor using ~50W.

https://discussions.apple.com/content/attachment/53810b76-01b0-4316-a672-5326d730c8ee

Now, I stick with my original question, why the older tb4 can negotiate the power but not the new one? I tested also with a smaller OLED monitor, same issue.

If the monitor worked with the older MBP, using the amount of power that you showed us in your previous photo, you got lucky. That amount of power was well below what the manual monitor said that the monitor wants, even though both MBPs were within their rights to offer that amount of power – or less.

The USB 3.0 standards only call for host ports to offer 900mA of 5V power (i.e., 4.5W), so if the MBP was giving the monitor 12W, whether through PD or through the monitor just taking it anyway, that was well in excess of the amount that the MBP needed to provide as per USB 3.0 specifications.

As for Power Delivery power, I could be mistaken, but I do not believe that either MBP was required to offer any of that at all. Apple advertises that the MBPs can charge over USB-C, not that they charge other devices over it.

Now you are showing us a photo where your portable monitor is drawing 2.49A at 20V – for a power draw of 50W. This from a monitor whose specifications say it uses 17W, and whose manual implies that a 15W supply would be sufficient and a 30W supply would be recommended.

OK.

That picture shows that the monitor is getting power when attached to the new MBP. It just isn't getting signal. I was under the mistaken impression that the monitor was showing nothing at all, as if it did not have its own power source, and was not getting power from the MBP, either.

That first link leads to a page for several monitors. Yours is appears to be the J5.

The J5 is a 17.3" monitor with 3840x2160 pixel resolution and a 60 Hz refresh rate. It has two USB-C inputs and a HDMI input, plus a downstream Micro USB-B port. The specifications say that it does not have a built-in battery – and that its rated power is 17 watts. The monitor has an IPS panel and 100% coverage of Adobe RGB – both good specifications that don't matter for the purpose of troubleshooting here.

3840x2160 @ 60 Hz is bog-standard and well within the capabilities of your MacBook Pro, whether you use one of the MBP's USB-C ports, or use the MBP's HDMI port.

Here's the manual .

In Chapter 3 of the manual, under Type-C signal transfer, and again under HDMI signal transfer, they say

"Note: 4K monitor needs higher voltage power, for a more stable power supply, it is recommended to use our original PD adapter to power."

In Chapter 6 of the manual, under Q&A, they say

"Q: The monitor keeps switching and flicker, although it connected to outlet for extra power supply.

A: This situation is generally caused by insufficient voltage. Please check whether the factory-packed cables are used, and then check whether an external PD power supply is used. The power consumption of 4K monitor is relatively larger, and an external PD power supply is required."

They also say that the monitor requires at least a 15W power supply, but that their power adapter provides 30W, so that if you use a power bank (external rechargeable battery), one "with output above 30W is recommended."

Part of USB-C Power Delivery is that the power supplier negotiates with the power consumer as to what voltage to offer. The original standard allowed power transfers of up to 5A at up to 20V (up to 100W); the current one allows power transfers of up to 5A at up to 48V (up to 240W).

If I look at the fine print on the bottom of a 29W Apple USB Type-C power adapter, I find the words "Output: 14.5V === 2.0A (USB PD) or 5.2V === 2.4A." Both my MacBook and my iPhone charge off this adapter, but if either was picky enough that they would not accept anything less than 20V, they would be in trouble.

So the highlighted parts of the monitor manual raise some follow-on questions:

• What "higher voltage" does the monitor expect?
• What voltage is the old MBP offering?
• What voltage is the new MBP offering?
• Could the voltage that the new MBP is offering be high enough to let the screen come on and display that "No signal" message, but not high enough to let the electronics to receive a signal work properly?

Remain calm. Don't get distracted by ThunderBolt-5, it simply is not a factor here.

ThunderBolt-5 cables and ports run differently ONLY when each and every device involved is genuine ThunderBolt-5. Otherwise, they are indistinguishable from ThunderBolt 4 and ThunderBolt-3, which are electrically identical and barely different from each other, except by some arcane support for multiple devices on one cable.

When All devices are Thunderbolt-5, the regular baseband data stream (one bit per signaling interval) changes to a modulated signal (3-patterns per signaling interval) for increased speed. Nothing else of substance changes.

when all devices are NOT Thunderbolt-5, it all works as if it were Thunderbolt-3. If connecting only USB devices, it all works as USB devices.

-------

Readers here report that main issue for Bus Powered Displays is that they don't get enough Bus-power using one port.

You can check whether the device is getting all the power it needs by invoking:

 menu > about this Mac > (system report) ...

... and checking this display:

...