[kmeisthax]

So, there isn't enough internal volume to fit an A and C port in the same slot. Ports require more volume than they appear. But I'll interpret this to mean: "why can't we have one USB-C port with all the altmodes and another with just USB 2 or 3, no altmodes, no power/data role swaps, etc".

USB 2 is possible, for some really dumb reasons. USB-IF actually prohibits repurposing the USB 2 pins for other purposes in USB 3.x capable connectors; effectively making it a separate bus from everything else. So you can route the USB2 pins on both C connectors to a hub chip and route everything else from the "privileged" port to the inner port. You will still need some kind of power mux so that the USB 2 port still gets power regardless of what port holds the power role.

This technically breaks the USB-IF rules[1] because you aren't supposed to disassociate the USB2 and 3.x pins like that. In practice as long as every device sees either just 2.0 or both 2.0 and 3.x pins, it's fine.

USB 3 onwards is a problem because of altmodes. The 3.x pins are officially referred to as "high-speed lanes" in the USB-C spec, because there's two of them and they don't have to carry USB 3.x. Every altmode[0] exclusively repurposes the high-speed lanes for some other kind of traffic. So USB 3 is effectively an altmode in and of itself. If you put a USB3 hub on those pins, then you lose altmodes, unless you have that magic hub silicon that doesn't exist that I mentioned in the parent comment.

[0] The USB2 lanes are forbidden to be reused by altmodes. Which is why VirtualLink is incredibly cursed.

[1] Yes I actually have mentioned this sort of thing in the Framework forums, no they won't actually sell a card like that. Consider it an EE exercise for curious Framework users.

[JoshTriplett]

Thank you for the detailed comment!

You'd definitely need a smart hub chip, yeah. But I don't think you need all the altmodes. No analog audio, for instance. Primarily Thunderbolt, and power.

I'm interested in the volume question; what makes USB-A and USB-C unable to both physically fit in the space no matter how creative you get?

[kmeisthax]

The footprint of the receptacle is wider than the actual plug that goes into it, by a significant amount. It only looks like it'll fit from the outside.

Analog audio was just me being exhaustive, I'm pretty sure none of Intel's chips support that altmode natively. Hell, only like half of the market of USB-C phones support it, which makes it mildly cursed.

[JoshTriplett]

> The footprint of the receptacle is wider than the actual plug that goes into it, by a significant amount. It only looks like it'll fit from the outside.

To what degree is it impossible, and to what degree is it challenging? I've seen the internal side of a USB-A port, and while it's slightly larger, it doesn't seem excessively so.

(Also, as an aside, I do wish that Framework had made the two expansion slots on each side adjacent and allowed for double cards that take up both slots. Two USB-A and one USB-C in one double-bay, for instance.)

> Analog audio was just me being exhaustive, I'm pretty sure none of Intel's chips support that altmode natively. Hell, only like half of the market of USB-C phones support it, which makes it mildly cursed.

Yeah, it's cursed that there exist USB-C-to-headphone-jack cables that physically plug into a laptop but will never work.