Most modern USB 3.0 hosts use eXtensible Host Controller Interface (XHCI) USB controllers. The XHCI specification allows for a massive 7,906 enpoints! However, common implementations of the XHCI controllers impose their own limit on the total number of endpoints to 96.
те 96 максимум
A single USB host controller can allow up to 127 connected devices. A connected USB hub counts as a USB device address, and every device connected to it goes towards the maximum allowed addresses for that one host controller.
тут 127