>> Does Windows guarantee that the DeviceAddress value is always > 0?
>
> The field is unsigned short, so yes.

Ah you meant > 0, not >= 0.

I already partially answered that, but my current assumption is that 
Windows will never let a device that has a DeviceAddress of 0 be 
accessible, since it wouldn't have been able to fetch the data 
(descriptors) it needs to have to instantiate it.

We do issue an IOCTL to a hub to get the DeviceAddress, so there's still 
a remote possibility we get a zero if we're unlucky enough to query the 
hub before low level OS initialization is complete.

However, our querying of the hub is tied to already having identified a 
device instantiated by Windows, and trying to populate some of its data. 
Thus that DeviceAddress 0 entry we see should be an extra entry that 
will be dropped, as failing to matching anything we know.

Regards,

/Pete




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