Description of problem:

Since the upgrade to mga5, I cannot see anymore the battery level of my Logitech mouse, using the Logitech Unifying Receiver. I had this battery level in the KDE notification zone.

I tracked down the problem to upower, who cannot see my mouse anymore.

In fact, I found a similar bug in Fedora bugzilla:
https://bugzilla.redhat.com/show_bug.cgi?id=1205916

Following the information in this bug, I've been able to get my mouse battery showing again.

I copy the remaining of the Fedora bug here, as it solved my problem:
=====================
/usr/lib/udev/rules.d/95-upower-csr.rules has the rules for Logitech Unifying Receiver device:
--
> ATTRS{idVendor}=="046d", ATTRS{idProduct}=="c52b", DRIVER=="logitech-djdevice", ENV{UPOWER_BATTERY_TYPE}="unifying"
> ATTRS{idVendor}=="046d", ATTRS{idProduct}=="c532", DRIVER=="logitech-djdevice", ENV{UPOWER_BATTERY_TYPE}="unifying"
--

Seems that DRIVER name in udev has changed (4.0 kernel?), so that it has no logitech-djdevice anymore:
--
# for f in /sys/bus/hid/devices/*; do udevadm info $f | grep DRIVER=logitech ; done
E: DRIVER=logitech-hidpp-device
E: DRIVER=logitech-djreceiver
--

By changing DRIVER to logitech-hidpp-device (or copying it to /etc/udev/rules.d and changing there) I was able to match my receiver:
--
ATTRS{idVendor}=="046d", ATTRS{idProduct}=="c52b", DRIVER=="logitech-hidpp-device", ENV{UPOWER_BATTERY_TYPE}="unifying"
--
=======================

Then I can get the info for my mouse, and the KDE plasmoid works again:


[fred@localhost ~]$ upower -i /org/freedesktop/UPower/devices/mouse_0003o046Do4009x0006
  native-path:          /sys/devices/pci0000:00/0000:00:1a.1/usb4/4-1/4-1:1.2/0003:046D:C52B.0003/0003:046D:4009.0006
  vendor:               Logitech, Inc.
  model:                M315/M235
  serial:               840E6474
  power supply:         no
  updated:              sam. 25 juil. 2015 17:40:44 CEST (104 seconds ago)
  has history:          yes
  has statistics:       no
  mouse
    present:             yes
    rechargeable:        yes
    state:               discharging
    warning-level:       none
    percentage:          70%
    icon-name:          'battery-full-symbolic'


Reproducible: 

Steps to Reproduce: