Multiple light sensors

[Richard Hughes]

After looking at the code in:

http://gitweb.freedesktop.org/?p=hal.git;a=blob;hb=HEAD;f=hald/linux/addons/addon-macbookpro-backlight.c
http://gitweb.freedesktop.org/?p=hal.git;a=blob;hb=HEAD;f=examples/light_sensors_and_keyboard_backlight.py

I see that the GetBrightness comes back from HAL as a "ai" value, i.e.
an array of signed integers.

org.freedesktop.Hal.Device.LightSensor.GetBrightness should probably
only return with a single percentage value like the other providers of
GetBrightness.

I think if a machine has multiple light sensors then they should be
exposed as separate "devices" rather than use light_sensor.num_sensors
and pretend it's a single device.

I'm currently adding support into g-p-m for light sensors, and having to
have two different code paths for get_brightness (depending on device
type) seems very clunky to me, and not at all abstract.

Comments? Flames?

Richard.