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by Nextgrid 2212 days ago
As far as I know the spec doesn't allow it for some reason. I guess one reason could be the power side (which I haven't mentioned and I am not familiar with it)?

Let's assume the hub requests 19V from the upstream port. Unless it has built-in, variable, per-port voltage regulation, it will not be able to respond to power requests from the downstream devices if they differ from what is coming from the upstream port.

This isn't a problem when providing USB-A ports because you either request 5V from upstream and pass it through or request a higher voltage and have a single 5V regulator and pass its output to the downstream ports.
1 comments
Kirby64 2211 days ago
See, you could technically design something that does that. Per-port up to 100W charging it definitely possible. Basically you have a USB PD controller on every port with dynamic voltage control.

This is all possible, it's just a HUGE pain in the ass (and costs a lot) to design that way. The problem is you essentially end up with potentially a giant, VERY expensive USB hub. And no one wants to spend $400 on a USB hub.

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Nextgrid 2210 days ago
Which is why USB-C is bad, nobody asked for a protocol where the benefits are marginal but the downside (one of many) is that a proper hub that replicates the behavior of previous generations now costs more, and since nobody would pay that much, economies of scale don't apply and thus it doesn't exist at all or is available as very niche specialized units (kinda like opto-isolated USB hubs which go for $200.

You could also theoretically use 10Gbit Ethernet to transfer data from your phone but we don't go around putting SFP slots on phones because we don't want every single cable or charger to cost $100 and be more complex (thus more prone to failure) than needed.

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Kirby64 2210 days ago
The thing is, you're not replacing it with something identical. If you want to replicate the behavior of a previous generation USB2 hub, I don't think it would even be that expensive. You just need a USB port controller on each port and negotiate 5V, 1.5A on each of them in addition to the standard USB hub. It would be a bit more expensive, but not terribly so. USB3 may be similar but require some extra switches...

The ask for the 'really expensive' $400 one has vastly more options and capabilities than the traditional USB hub. It's basically a Thunderbolt hub with even more complexity, so it's not unreasonable to think those would be damn expensive.

I'm honestly not sure why no one has made a standard USB2.0 Type-C hub. There's really nothing stopping you from doing it. I guess maybe because it could be confusing for a consumer? I agree, that's a huge issue with Type-C right now. It's very unclear by looking at the port (or the cable) what it's actually capable of. If you're lucky there will be a tiny symbol indicating some subset of functionality, but often times there isn't.

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