NixOS/nixpkgs — pull request #942 by grwlf (2013-09-07 19:39:38+00:00)
Title: Upower local libusb revert

That workarounds the coldplug problem

$ sudo ./libexec/upowerd -v
TI:18:38:27 Starting upowerd version 0.9.19
...
TI:18:38:27 registering subsystem : usb
TI:18:38:27 failed to coldplug /sys/devices/pci0000:00/0000:00:1c.4/0000:03:00.0/usb1