MacBook Pro M4 with thunderbolt 5 and portable monitor

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.

This is close to showing it's not just you.

MacbookPro 2019 USB-C

Portable monitor with no external power--just plugged into the MB port

Using USB-C Cable. Perfect

Using cable that came with monitor. Perfect

Using the NEW APPLE BRANDED TB5 CABLE. Perfect.

New MacBook Pro M4 Pro

Portable monitor with no external power--just plugged into the MB port

Using USB-C Cable. No signal

Using cable that came with monitor. No signal

Using the NEW APPLE BRANDED TB5 CABLE. No signal

I came across this:

USB4™ Thunderbolt 3™ Compatibility Requirements Specification – Version 1.0 (February 2021)

This specification pertains to Thunderbolt 3 ports that are also USB4 ports.

It sounds like if a system has a single USB4 / Thunderbolt 3 port, that port must provide 15W of power. When a system has multiple USB4 / Thunderbolt 3 ports, only one out of every four ports has to provide 15W (5V / 3A). From what I see here, it sounds like a M-series MacBook Pro would be standards-compliant if it offered 15W on one of its three USB4 / Thunderbolt ports, and 7.5W (5V / 1.5A) each on the others.

A MBP could offer more power, including power at higher voltages, but that would be optional.

"A USB4 Host may optionally provide 15W or more power on a USB4 Port via explicit PD contract."

I don't know of any Apple Technical Specifications or Support documents that spell out clearly how much power any particular Macintosh is willing to provide on its USB-A, USB-C, USB4, or Thunderbolt ports. You could infer that a USB-A or USB-C port that supports USB 3.0 speed or better must be willing to provide 4.5W (5V @ 0.9A) without Power Delivery negotiation, since that's expected of USB 3 host ports, but good luck in finding that out from Apple's documentation alone, if you had never heard of the USB 3 limits separately.

So we're working somewhat in the dark as to what the "expected" power delivery specifications are for old & new MBPs – and whether the behavior change is, from Apple's standpoint, an unintended change or an intended one.

The Inateck HB2030 hub arrived today, and I tested it by connecting it's USB-C lead to one of the Thunderbolt 5 ports on the back of the M4 Pro Mac Mini, and from the DP USB-C port on the hub to the Arzopa 2.5k 16" portable monitor, using the USB-C cable that was supplied by Arzopa. Sadly, the work around did not work as hoped! Power was delivered to the screen, but not simultaneously with video signal. Curiously, if I then connected the HDMI cable from the HDMI port on the hub to the mini-HDMI input on the portable monitor, then it did work. So the video signal and power coming from the TB5 port did managed to power and supply video, but only when the video was coming through the HDMI port on the hub!!

Your post mentioned the 10Gbps or greater USB-C video/data cable - I am not sure what the cable that was supplied from Arzopa is, but I imagine if it works with a TB3/4 port it should work with this hub also.

Hmm.

Out of curiously and to test my theory, have you upgraded to 15.0?

I posted a comment just now, but don't know how to link it as I just signed up to post on here the first time because this is frustrating me so much. The gist of it was "I got the m4 Pro upgraded to Sequoia, monitor wouldn't work. After a few days decided to got back to my M1 for the time being, had to update as my last Time Machine was on Sequoia and now even it won't detect the monitor when it was perfect right before hand"

Servant of Cats,

You ask..."Please provide a link to the Technical Specifications which state that

the M4 Max MacBook Pro will provide large amounts of power – in excess

of the minimums for USB or Thunderbolt ports – to an accessory. I am

looking at the stated specifications, and I see nothing to that effect

there."

I as an impartial observer can understand the consternation some might have about this.

Their older, less expensive equipment is supporting the hardware that their newer hardware is not.

Apple has a history of declaring equipment vintage:

Obtaining service for your Apple product after an expired warranty - Apple Support

And then not offering system upgrades for those equipment eventually making it difficult to find more current software for their Macs.

To buy all these peripherals only to find new equipment no longer supports it is a very hard blow.

It is my firm belief for people who suddenly get surprised because some older hardware is no longer supported, to go both to the manufacturer of that older hardware and ask AppleCare to look into the issue to see if one or the other can offer some firmware update to fix these issues. I wrote this tip to show that this isn't isolated to Apple, but an ongoing issue with standards of USB-C and Thunderbolt across the industry.

USB/Thunderbolt & Energy Saver/Sleep/powe… - Apple Community

Just because the specs do not say something is directly not supported, past history of supports lends to the misimpression they should have continuous support. Calling it a newer Thunderbolt or USB-C lends to the impression it should be able to support what the older Thunderbolt or USB-C did. This is where communication is key. That customers reach out to both Apple Support (AppleCare) and the manufacturers of the devices to find out where the actual support broke down with newer equipment.

David S. wrote:

I asked Plugable Technologies to test its USB-C portable monitor for laptop (USBC-PDMON) which has 2x 10Gbps USB-C ports for data or connecting peripherals, 100W PD pass-through (85W charging), 15.6” IPS display, cover/stand with a M4 Pro 14" MacBook Pro using one of the T5 ports. Looks like it works:

We've tested the USBC-PDMON with a MacBook Pro (14-inch, 2024, M4 Pro) and they worked well together. The portable monitor was able to successfully show video from the Mac, and the other functions such as the 10Gbps USB hub ports and Power Delivery pass-through also worked well.

Just passing that information on to those who are interested. Obviously contact the company to make certain before you buy it.

Exactly WHERE were they connecting the power supply? All these displays work if you connect a power adapter to the DISPLAY. The issue is whether they can negotiate to get enough power from the Mac across ONE interface from the MAC's ThunderBolt-5 port.

I have spent about 16 hours total now trying to find a way to simply be able to connect external displays with just one usb-c cable per display (power and a/v) to my MacBook Pro M4 Max with no success. I can do this with a MacBook Pro M1-4 non-pro/max chip computer without ThunderBolt 5 ports and am so disappointed that this appears no longer to be possible; Apparently the TB5 ports don't provided sufficient power any longer as with my 10+ year old POS MacBook Pro... I have ongoing cases with Apple at the moment but it seems they are just humoring me. Currently, without a docking station, I can only get ONE display to connect as long as I'm providing external power—a second monitor is not permitted. I have sent videos and logs. Seems like a step backwards...

I travel for work and in the airport, I need to be able to function without plugging into an outlet and pack up quickly. Anyone else find a solution? Below is my preferred setup when traveling (really at home even) and was my 14" MacBook Pro M2 with L Limink detachable 14" monitors with only 2 USB-C 4 cables...

I’m not sure this is Apple’s issue to fix since this is an incompatibility of the monitor with Thunderbolt 5. It's generally a manufacturer's responsibility to release firmware updates to make their products compatible.

The only way the onus would be on Apple to correct anything would be if their implementation of TB5 were somehow faulty — which absolutely could be the case; I just personally don't think it's that likely.

Edit: Unfortunately I also get the impression that Arzopa is the kind of company that won’t bother releasing those firmware updates and instead will release a new product with the updated firmware included instead. (Also added a paragraph break)

in that presentation, click graphics/displays to see what port and what rules {thunderBolt, USB, other} are governing that display.

then go to that port and see what's up.

You have not talked about ONE specific model display, so all we can do is talk generalities so far.

Computer problems often have MANY moving parts, and very, very, very, often the actual causes are things that were NOT on your original suspects list.

For example, many display problems today are caused by cables that are perfectly good, but are not up to a high enough standard to do the jobs they are being asked to do.

You keep telling readers you tried multiple displays and all must be unsupported and therefore Macs are defective.

But to help you, we need to be able to replicate at least the specs of what you are using, and make certain it is all reasonable and there are no obvious distractions provided by any assumption or experimental setup error or mistakes you might be making.

We keep asking you to please do your due diligence and report to us the EXACT experiment setup you are using, in complete detail, including:

• EXACTLY what make& model display you care about (so we can look up its specs and be certain it should be expected to work in these circumstances)

• EXACTLY what cables and adapters, including whether they are certified, or have Trademarks on them, and about HOW LONG they are. (Some are known to not be adequate.)

• EXACTLY what is connected to what, and if the problem persists after a Restart if you do not change ANY cables.

You have nothing that requires or can use Thunderbolt anything, and certainly not Thunderbolt-5. You paid dearly for that ThunderBolt-5 cable, and it seems to be a complete distraction in every way.

I recommend you try using a simple USB-C cable one meter or shorter, and see if that allows it to run the way you expect.

Longtimeusers1014--

the appropriate response in that case is to ask the display maker why a known-good sample of their product does not work with the latest MacBook Pro M4 PRO. The manufacturer has the Engineering expertise to find out why, and if it turns out to be a computer problem, to pressure Apple to fix it.

You will, of course, need to provide enough information about your setup so that they can duplicate and instrument that system in their lab.

Having the same issue. Just bought a UPERFECT 4K display. No signal on my MBP M4. Works just fine on any other computer.

Seeing conflicting reports here of whether a TB5 cable will fix the issue. Right now I can hook it up via 2 cables (HDMI and USB-C for power) and it works, but that's obviously not optimal.