MacBook Pro M4 with thunderbolt 5 and portable monitor

This works if your monitor has two USB ports:

1. plug portable monitor into a charger so it can get power.
2. Then plug it using a second cable into the M4 (thunderbolt) so it can get signal.

Mine kept saying "no signal" when I guess it really meant "help no power!"

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:

...

Thanks for the info Grant, but I can’t seem to find any reports of how much power my monitor is requiring. 

The first picture shows my M2 pro, which although is powering my monitor, the only reports are of a Keyboard requiring 100 mA, and a mouse requiring 100 mA. 

The second picture shows my M4 pro, which shows a keyboard requiring 98 mA. My M4 is connected to the same monitor but is being powered separately. If I was to disconnect the external power I couldn’t see anything even if there was something to see. 

If I click on Thunderbolt/USB4 I get the same result as dragos, No device connected

For sake of argument, have you taken your Mac to a Best Buy to see if any other monitors work better?

It could be there is a needed firmware update, or something has worn.

For sake of argument, have you made a copy of an older operating system to see if indeed it is the OS update which is incompatible as you claim?

You can use internet recovery to install an older OS on a separate partition of your Mac, the OS that shipped with the Mac.

Grant has a good point. The System Profiler makes it obvious why some of these issues exist.

USB/Thunderbolt is still serial. If you know anything about serially connected electronic devices they all work based on the weakest link of the chain. Have webcam in the mix? Its power will bring down the whole bus to the lowest power speed denominator. Have a USB-2 cable on one bus of the CPU, that's all the speed you'll get from the device. Wall powered hubs and docking stations help alleviate power drains on the built-in USB bus of the computer.

When Apple first adopted USB-C in 2016, I was stunned how a bus powered external hard drive was never seen through the hub, unless it had enough power passing through.

So dig through the profiler closely to see what's draining power and speed.

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.

if your display connects as a Thunderbolt device, it may not support obtaining power from the Mac.

if you display connects as a USB device, it may support being powered by the Mac's Bus power

I have lost track of what your fundamental question is through all of this.

¿could you lay out the case again, and what you are trying to determine?

Sorry for the confusion Grant, I seemed to have hijacked dragos's original post with my own different one.

I was just wondering why my M4 Pro Mac mini can't do what my M2 Pro Mac mini does, i.e. power the same 15 inch portable monitor on its own without requiring external power, I'm using the same cable on both. Could it be something to do with the Thunderbolt 5 port.

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.

Thunderbolt-5 only shows as available on the 7 port models, which are the 14" and 16" models.

The 13" and 15" model only show Thunderbolt 4 on Apple's website.

Use a 20" ruler or tape measure and take it to the screen diagonally to figure out its actual measurement.

https://www.tomsguide.com/computing/thunderbolt-5-vs-thunderbolt-4

The true lithmous is the amount of charge your Mac gets when hooked up with a 240W charger.

If they only get significantly less, then there is something to be said about that. Both Dell and HP have CAD/GIS laptops that uses two Thunderbolt ports together to achieve higher wattage. It sounds like from the spec, thunderbolt 5 seaks to offer that without the extra cable.

USB-C Power Delivery provides a mechanism to negotiate the delivery of power in either direction.

It doesn’t mandate that devices be willing to provide power, though. It only provides a negotiation mechanism and a standard for power delivery for those that do want to provide it.

You seem to be confusing your desire to power a display off the MBP’s battery for a standards based mandate that the MBP must provide that power. And you keep refusing to help people with any specifics that might help someone to figure out what is the case.