Hi there. I have 3 identical devices, all hooked up to a usb hub, and that hub connects to a port on the Fedora 22 computer running cgminer  4.9.2.

When it first started, the cgminer was seeing all the devices, but now, without changing any configuration,  it says that one of them is inactive.

Bus 2 Device 6 ID: 10c4:ea60 Silicon Labs CP2102 USB to UART Bridge Controller Active
Bus 2 Device 5 ID: 10c4:ea60 Silicon Labs CP2102 USB to UART Bridge Controller Active
Bus 2 Device 4 ID: 10c4:ea60 Silicon Labs CP2102 USB to UART Bridge Controller inactive

and therefore, it only sees 2 devices running and the mining has slowed down by 1/3.
I tried USB  Enable,  Whitelist, etc, nothing helped.. Power off/on was tried many times as well.

The 3 devices look OK physically. Power supply LED's lit, device LED's lit, fans running.

What else should I check?
Thanks! -t