I connected a USB mouse to a notebook running Ubuntu 14.04. The mouse was not detected. In fact, it turned out that no USB device was being detected on connecting to the notebook.
To eliminate hardware error, I rebooted into Windows. The USB mouse was detected and worked fine on it!
On rebooting back to Ubuntu, I noticed an error message involving USB just because the Ubuntu desktop was displayed. On looking in
/var/log/syslog, I found error lines of this form:
usb 3-7: device not accepting address 2, error -62 usb 3-7: new full-speed USB device number 3 using xhci_hcd usb 3-7: device not accepting address 2, error -108
No amount of searching and trying fixes seemed to help. I thought that this is a software driver problem. I also wondered how the same hardware and software had worked well just a couple of days ago. What could have gone wrong in 2 days on this notebook where nothing had been touched or tampered with?
After looking high and low, I finally landed on the strange post by Paul Philippov where he suggested that this could be due to the USB hub or ports being hot or drawing too much power. I noted that the notebook had been running for many days now. Could some fickle cooling problem have caused this?
I shutdown Ubuntu and left the notebook powered down for 15 minutes. I powered back on and all the USB ports worked! What a strange solution!!! 😊