Hi,
If you have multiple USB2 devices, we would suggest use more USB2 roothubs in Xavier. Please check product design guide:
https://developer.nvidia.com/embedded/dlc/jetson-agx-xavier-series-oem-product-design-guide
There are usb2-0, usb2-1, usb2-2, usb2-3. If only single roothub is used, EP number is limited and also bandwidth:
connected more than two usb cameras problem on deepstream-app (Jetson Nano Dev Kit) - #12 by DaneLLL