USB issues with APC UPS

[xawen]

I'm having a strange issue with a new UPS and I'm not real sure where to start troubleshooting.

I have a new APC NS 1080VA UPS. I'm trying to attach it to a whitebox server running CentOS 6.5 (fully updated) so the automatic shutdown functionality can be used.

Every time I attach the USB port on the UPS to the server, the USB subsystem starts having issues. Any of the apcupsd tools freeze as soon as they try to access the USB port and can't be killed. Attempting to "cat /proc/bus/usb/devices" freezes and is unkillable. That stays locked up even if I disconnect the UPS, it takes a full reboot without the UPS connected to recover. Connecting new devices after the UPS seems to be hit and miss...but I haven't gotten consistent results with that yet. I do have an external USB hard drive on the server that continues to work regardless of what else happens.

I have no idea where to start in trying to figure out what's going on. I did hook the UPS up to a Windows laptop and it's working normally, so I think the hardware is fine.

Anyone have any suggestions?

-----------Edit---------

I forgot one more detail. The UPS is detected correctly in the kernel log when it's plugged in. The correct model and serial information is listed, but that's the last I ever see of the device.

[drk]

Hmm, I've used the USB cable models of APC UPSs quite a bit and didn't see anything like that. Off hand I'd make sure that you're plugging it into a USB2 port and not a USB3 one.