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Comment by bombcar | Hacker News Reader

What's annoying is that the "Thunderbolt" connectors ALSO depend on the chipset internally (and how it is routed) - for example on my MacBook Pro (15-inch, 2017) - I can drive four external monitors but ONLY if I connect two on each side of the laptop. I have two daisy chained via Thunderbolt but I cannot use that second Thunderbolt port on that side for a third monitor - it must be on the other side.

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If I understand your issue correctly, this is a macOS issue, where macOS only support DP daisy-chain (MST "Multi-Stream Transport") for mirroring content, not multiple screens.

https://medium.com/@sebvance/everything-you-need-to-know-abo...

(I stumbled upon this limitation myself recently. Supposedly Windows doesn't have this limitation though I haven't tried it myself)

I don't know what I'm technically using, but it's two monitors daisy-chained via Thunderbolt and they're not mirrored.

System Report says "Thunderbolt 2" is how they're connected.

Part of it may also depend on the dock and how it routes the TB lanes. My dock uses 2 lanes for dock features and does passthrough for the rest. Are you able to daisy-chain your monitors off any of those ports without the dock in the path?

I have no dock at all (though technically the monitors may be a dock).

Apple Thunderbolt 3 to Thunderbolt 2 cable -> 34UM88 -> Thunderbolt 2 to Thunderbolt 2 cable -> 34UM88.

To make it even more fun, Thunderbolt 3 looks like USB-C and Thunderbolt 2 looks like Mini DisplayPort.

https://i.imgur.com/5TJaIqg.png

(Technically I do have a dock but it's on the other side and is unrelated).

To make it even more fun, Thunderbolt 3 looks like USB-C and Thunderbolt 2 looks like Mini DisplayPort.

What do you mean? Thunderbolt 3 uses USB-C connectors. And you can also use a Thunderbolt 3 cable as a USB 3.1 Gen2/DP-Alt/PD cable.

The big annoyance is that it doesn't work the other way around. There are even USB-C cables that only carry USB 2.0 and do not have the SuperSpeed lanes. So, they are not only worthless for Thunderbolt 3, but also for getting good tranfer rates using newer USB revisions. Worst of all is that there is no cable marking system.

Exactly - I have no easy way to tell if something is "USB USB-C" or "TB3 or TB4 USB-C" especially on the adapters. It's frustrating getting everything hooked up.

it's hilarious you know. for almost 20 years we had this perfect "it sits it fits" approach to usb, now here we are, four standards three cables one connector. easily avoided by just keeping a different connector for each spec...

We even had USB 3.0 type B (a connector that take two different kinds of USB type B) - but we've moved on from that. It's understandable that if you have a interface that is compatible with another (Thunderbolt 3 can run USB 3.2) that the connector is the same, but it's frustrating.

At least usually you'll get something that kinda works.

The USB-C connector isn't for USB3. It's for any version of USB. It's perfectly valid to have a 1.1 12Mbit HID using the USB-C connector.

I didn’t say that. I even mentioned cables that only carry USB < 3.

At least you have USB-C on both sides. Dell is shipping 'professional' laptops with USB-C on only one side.

But does it have the problem GP is describing?

If not, I'd say it's definitely better than his/her MacBook Pro since they're at least functioning.

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