Chosen Solution
Does anyone know how many individual thunderbolt 4 and USB 3 controllers are in here. I’m trying to determine the maxim attachment limits. Update (01/11/2023) For those who wonder I can now confirm a few things. At least for the ultra. Let’s first mention that the M series chips, like apples later A chips, DO have USB controllers. It’s a logical, or soft controller implementation in the chip’s ISC but it’s still there. Based on power draw testing the thunderbolt ports are individually powered. I don’t have 127 devices to test my theory, but I believe each port is solo control. Second, the two usb A ports are shared; a single controller. I guess hands-on puts it to rest.
I can’t say for certain, I would need access to good views of both sides of the logic board for one of these, plus the schematic, which I don’t expect will make it into the wild any time soon. But here’s what I can tell you based on the information I have from other Apple Silicon based Macs and the board hardware. The 2021 14" MacBook Pro makes use of 1 Texas Instruments CD3217 USB C Port/Power Delivery Controller and 1 Thunderbolt Retimer per USB C port. Data lines for the Thunderbolt retimer go basically straight to the SoC (no other chips, just small basic components). As for how the SoC handles it, I can’t say for sure. But there are no longer “Thunderbolt” controllers like you you see on Intel devices. Like so many other things that used to have dedicated controllers, its built into the “processor” (of whatever flavor– Pro, Max or Ultra). I don’t know that that will be much help to figure out your setup, hopefully it will mean you can consolidate some. But it’s hard to say in practice.
The SoC chip dictates how many are TB3 ports. The Ultra gets all four USB-C connectors as TB3, unlike the Max only has the rear ports as TB3 and the front ports are limited to USB3.2. Each TB3 ports are dedicated unlike the USB3.2 ports.
