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Platform Capture Setup for Bus Scope: Setup and Workflow Guide

Linux usbmon

usbmon is a kernel facility that exposes USB traffic through debugfs.

Enable:

sudo modprobe usbmon

Verify:

ls /sys/kernel/debug/usb/usbmon

You should see numbered monitor interfaces (0s, 1s, 2u, etc.) — one per USB bus.

Permissions: By default, only root can read usbmon. To grant user access:

  • Add user to the appropriate group
  • Or sudo chmod a+r /sys/kernel/debug/usb/usbmon/*

Bus identification: lsusb lists connected devices and their bus numbers. Match the bus number to the usbmon interface.

Windows USBPcap

USBPcap installs as a driver that captures USB traffic at the root hub level.

Root hub selection: USBPcap shows available root hubs. You must select the hub your device is connected to. Use Device Manager to identify the correct hub by viewing "Devices by connection."

Driver binding: USBPcap sits below the device driver. It captures after driver binding — pre-enumeration traffic may be missed. For enumeration debugging, Linux usbmon is preferred.

Related workflows