winapi - How does windows identify a USB device uniquely? -


how windows identify usb device uniquely, though device data supplied usb device common devices of make ? state alternatively, windows can distinguish between 2 instances of dell keyboards of same model, without keyboard supplying unique serial number. exclusive data field windows searches when initializing usb device ?

windows uses device instance id identification. can see in documentation contains device part , instance part.

the device part taken usb device.

it bus driver how generate instance part. bus driver cannot solely rely on information returned usb device. because 2 identical devices break system - device instance ids must unique! appends additional info - port number , etc (the exact algorithms unknown , depends on driver manufacturer). pnp manager can add more uniqueness instance id.


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