[white-flame]

Across USB-C land, there's the various USB3s as well as Thunderbolt, DisplayPort, PCIe, and probably others, too, all sharing the same connector with arbitrary overlaps or omissions of compatibilities across the N-dimensional matrix.

[MBCook]

USB 4 is supposed to fix this by basically removing all the optionality.

Of course I don’t know how you tell if a device/cable is reliably USB 4 or not.

[dmitriid]

> USB 4 is supposed to fix this by basically removing all the optionality.

You mean, it's going to make it even more confusing by leaving in most the optionality. Intel's "Thunderbolt 4" certification removes (some of the) optionality. Detailed explanation here: https://old.reddit.com/r/UsbCHardware/comments/mjz2pu/usb4_a... and here: https://old.reddit.com/r/UsbCHardware/comments/mjz2pu/usb4_a...

Relevant quote:

--- start quote ---

Thunderbolt 4 is Intel's specific branding and certification program for its USB4 implementation. Thunderbolt 4 takes USB4, and turns on a bunch of the optional features and makes them mandatory (TBT4) requirements.

Among those optional features are:

- 40Gbps required (base USB4 spec allows 20Gbps-only hosts)

- Thunderbolt 3 backward compatibility (base USB4 allows host to skip TBT3)

- PCIe tunneling support required (base USB4 allows host to not support PCIe)

--- end quote ---

USB is a textbook study in how to design by committee and create easily avoidable problems out of thin air

[white-flame]

I hope they do like USB 3.0B and add yet another independent set of connector pins for 4.0, making it twice as large. /s

[MBCook]

I’ve only run into those once in real life but man what a mess of a committee’s design.

Actually let’s go back to DB-25. Each pin can be one “feature” so you can identify which features a device/cable support by looking for which pin(s) are missing.

[randy408]

Doesn't USB4 also introduce its own optional PCIe tunneling spec which isn't exactly the same as Thunderbolt?

[viraptor]

That's not a terrible thing, considering Thunderbolt is Intel-specific.