I have Dell XPS13 that I have just upgraded to SLED12 from SLED11 SP3.

The XPS 13 has 2 USB ports and with SLED11 SP3 both USB ports - USB3.0 on right hand side of keyboard and USB2.0 on left hand side of keyboard could be used when the laptop was running on battery or mains power to connect Logitech Wireless Mouse M525 using Unifying Receiver. This has worked flawlessly until upgrade to SLED12

With SLED12 and the machine running on battery power, the same mouse/receiver will not work at all on the USB3.0 port, when plugged into the USB2.0 port the mouse is almost able to be used but "lags" when moving the cursor on the screen. No lag when using the inbuilt trackpad.

When the machine is running on mains power the same mouse/receiver work perfectly (as the did with SLED11 SP3) plugged into either USB port.

If I unplug from mains power then mouse fails if plugged into USB3.0 and "lags" so is unusable in the USB 2.0 port.

Power related I think?
How do I change power settings?
Any other ideas on how to fix so mouse will work when laptop is running on battery power?

Thanks