When you are looking at /var/log/messages, you are doing that on that remote system, right? (I ask because that listing showing the hub, keyboard, and mouse being disconnected/reconnected sure looks like you did it on your local system.)
On the remote system, please run the "lsusb" command and post the output.
If, on that system, someone has done the equivalent of "Safely Remove Drive" on that device, then the USB port has been deactivated and will not respond again until either the cable has been disconnected and reconnected or else the system is rebooted. I've run into that problem with a front panel SD card reader that is connected to the motherboard via an internal USB plug. "Safely Remove Drive" on that device leaves it unusable until either the case is opened so that the connection to the motherboard can be removed/reinserted or else the system is rebooted.