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It might be worth noting that M1 Macs actually has two Thunderbolt controllers for 2 ports (dedicated controller for each port), whereas previous Macs shared tw
by sirn 6y ago
It might be worth noting that M1 Macs actually has two Thunderbolt controllers for 2 ports (dedicated controller for each port), whereas previous Macs shared two Thunderbolt controllers for 4 ports. The 2 ports limitation feels to me like a design decision rather than a hardware limitation (to differentiate with an upcoming higher-end model?)
- chrischen 6y agoThe distinction is moot since hubs don’t exist, so I’m still facing the problem of lack of physical inputs. At best on the market there are hubs that give 1 extra type c input for power.
- sirn 6y agoThere's a recently announced OWC Thunderbolt Hub[1]. I would still prefer to have 4 ports built-in even with two controllers rather than having to deal with hubs, though. [1]: https://eshop.macsales.com/shop/owc-thunderbolt-hub https://eshop.macsales.com/shop/owc-thunderbolt-hub
- chrischen 6y agoI did see this and it’s a bit sad that it’s been like 4 years since type c has come and hubs still aren’t generally available (even if just for USB and not thunderbolt). I mean I didn’t fully adopt USB type C just to convert the ports back to type A.
- sirn 6y agoThis is mostly because Thunderbolt hub support was optional in Thunderbolt 3 spec, but mandatory in USB 4. Apple just added support for it in Big Sur.
- Dylan16807 6y agoWhich leaves me deeply confused. Daisy-chaining had to be supported. From the host point of view, a hub is barely any more complicated. Why was it optional?
- sirn 6y agoMy understanding is that daisy chaining doesn't require a mixed USB and Thunderbolt signal, only Thunderbolt. Before USB 4, USB-C spec itself disallows hubs to passthrough an Alternate Mode and even Thunderbolt daisy chain also have to terminate at any point where USB is plugged in. In this case, I believe you can have Thunderbolt 3 hub that only carries Thunderbolt signal, but it will only work with Thunderbolt devices and not USB-C.
- Dylan16807 6y agoBut you don't need to mix signals. When you use a thunderbolt dock right now, doesn't it use pure thunderbolt as a backhaul, and have a PCIe-based USB 3 controller inside of it? If that's right, then even without mixed signals you could have a pure-thunderbolt hub, and you could have a device with several thunderbolt ports and several USB 3 ports. And it should be straightforward to combine them into dual-purpose ports. The rules for passing through alternate modes don't matter because you're not passing through, you're not a USB hub, you have your own USB root.
- sirn 6y agoThat indeed could work, and it looks like Belkin's Thunderbolt 3 Express Dock HD[1] actually does this. Though in this case, Thunderbolt is limited to just 2 (1 for downstream and 1 for upstream). I guess the biggest benefit of USB 4 hub is that allows the hub to have more than 2 Thunderbolt ports (the upcoming OWC Thunderbolt hub has 1 upstream and 3 downstream) and no longer have to worry about unplugging a device breaking a chain (usability problem). [1]: https://www.belkin.com/us/p/P-F4U095/ https://www.belkin.com/us/p/P-F4U095/
- chrischen 6y agoAlso doesn't exist for USB: https://superuser.com/questions/1381139/why-cant-i-find-a-usb-c-hub-with-multiple-usb-c-ports https://superuser.com/questions/1381139/why-cant-i-find-a-us...
- sirn 6y agoBefore USB 4, USB-C spec itself say "see also USB 3.1" for USB hubs and disallow passing through Alternate Modes (e.g. Thunderbolt/DisplayPort) or Accessory Modes (e.g. audio dongle) which vastly limited the usability of USB-C port. USB 4 introduces a new discovery protocol with added support for passing through Alternate Mode in USB-C spec (as long as downstream is also USB 4).
- outadoc 6y agoThe entry level MacBook Pro has always had only 2 ports, so this fits with the existing lineup. Most likely the next models to switch to ARM will get 4, like they do now.