I have an Ubuntu 15.10 machine that's exhibiting a strange usb error during startup.

The keyboard doesn't work during boot. The system gets to the login screen and, for something like 30 seconds, the keyboard doesn't work, but the mouse does. Then the screen blinks and the keyboard begins to work.

I have checked the system log and found

device descriptor read/all, error -110

and then, in awhile

usb 1-3: device descriptor read/all, error -110

usb 1-3: new high-speed USB device number 4 using xhci_hcd

usb 1-3: device descriptor read/8, error -110

usb 1-3: device descriptor read/8, error -110

usb 1-3: new high-speed USB device number 5 using xhci_hcd

usb 1-3: device descriptor read/8, error -110

usb 1-3: device descriptor read/8, error -110

usb usb1-port3: unable to enumerate USB device

usb 1-12: new high-speed USB device number 6 using xhci_hcd

usb 1-12: New USB device found, idVendor=046d, idProduct=082d

usb 1-12: New USB device strings: Mfr=0, Product=2, SerialNumber=1

usb 1-12: Product: HD Pro Webcam C920

usb 1-12: SerialNumber: 153D0E9F

usb 1-13: new low-speed USB device number 7 using xhci_hcd

usb 1-13: New USB device found, idVendor=413c, idProduct=2005

usb 1-13: New USB device strings: Mfr=1, Product=2, SerialNumber=0

usb 1-13: Product: DELL USB Keyboard

usb 1-13: Manufacturer: DELL

usb 1-13: ep 0x81 - rounding interval to 64 microframes, ep desc says 80 microframes

If I try to shut down (using the mouse) before the keyboard becomes available, I'm getting a black screen with the following messages appearing, one-by-one:

usb 1-3: device descriptor read/all, error -110

usb 1-3: device descriptor read/8, error -110

usb 1-3: device descriptor read/8, error -110

usb 1-3: device descriptor read/8, error -110

usb 1-3: device descriptor read/8, error -110

usb usb1-port3: unable to enumerate USB device

Any ideas on how to fix this? Is this a BIOS, hardware, driver, or service error?