Comment # 2 on bug 939191 from Bj�rn Lie

Yes to the extent that it's a dbus service that gets started by systemd, checks
if the HID hardware it's looking for is present, if not, it shuts down.

>From http://www.hadess.net/2015/05/iio-sensor-proxy-10-is-out.html

Modern (and some less modern) laptops and tablets have a lot of builtin
sensors: accelerometer for screen positioning, ambient light sensors to adjust
the screen brightness, compass for navigation, proximity sensors to turn off
the screen when next to your ear, etc.

Enabling

We've supported accelerometers in GNOME/Linux for a number of years, following
work on the WeTab. The accelerometer appeared as an input device, and sent
kernel events when the orientation of the screen changed.

Recent devices, especially Windows 8 compatible devices, instead export a HID
device, which, under Linux, is handled through the IIO subsystem. So the first
version of iio-sensor-proxy took readings from the IIO sub-system and emulated
the WeTab's accelerometer: a few too many levels of indirection.

The 1.0 version of the daemon implements a D-Bus interface, which means we can
support more than accelerometers. The D-Bus API, this time, is modelled after
the Android and iOS APIs.

====================

Note that this package is replacing functionality that is beeing dropped from
systemd v222 (it was dropped from systemd because of this package replacing
it).