If you have a USB 3.0 hub connected to your Pi and devices plugged into this hub are not configured properly, you check the logs and you see something like
device descriptor read/64, error -71
around USB activity – chances are that you ran into the same problem as several people, including the author of these words.
The conclusion is that USB 1.1 devices, connected to USB 3.0 hub are not working correctly in such configuration, due to a bug here or there, even if the very same hub, with the very same devices works well when connected to something else than Raspberry Pi. A workaround to this is to add an entry inside /boot/cmdline.txt
which forces the whole bus to 12Mbit/s USB 1.1 speed and lets you configure and use the devices.