Comment 15 for bug 808006

For those having problems, may I suggest to check that http://www.hostip.info/ really provides a location including a city, and checking that the following program will be able to retrieved the latitude and longitude :
http://developer.gnome.org/geoclue/unstable/simple-example.html

Then you may also want to check whether the following helps :
gtk-redshift -l geoclue:name=org.freedesktop.Geoclue.Providers.Hostip:path=/org/freedesktop/Geoclue/Providers/Hostip

After filling the details of the location of my IP on hostip.info, this helped :-)