Restarting USB subsystem in CentOS
After a long uptime specific (cheap) devices or components connected to the USB ports lock up or malfunction. Unplugging and plugging them usually fixes issues, but physical access to the system (especially a remote server) is neither always possible or desirable.
In cases like this, Linux (unlike Windows) can trigger a USB subsystem restart by deactivating and reactivating the USB controller(s).