Redshift/Flux/brightness-controller Stopped Working

I haven't used Ubuntu 16.04 LTS on my laptop for a while. Today, after I performed a system upgrade, it seems that neither Redshift nor Flux is able to change the screen color anymore. There's just nothing happening on the screen at all after I ran the commands.

Curiously, the screen color of the external monitor is changed just fine, it's just the built-in screen that's not responsive.

The brightness-controller utility is also not working, although the brightness control from system settings is.

They were definitely working well a few weeks ago.

In flux the following messages are shown:

/usr/lib/python2.7/dist-packages/fluxgui/fluxapp.py:75: GtkWarning: Cannot transform xsetting Net/IconThemeName of type gchararray to type GdkColor

gtk.gdk.screen_get_default().get_setting('gtk-icon-theme-name')
/usr/lib/python2.7/dist-packages/fluxgui/fluxapp.py:75: GtkWarning: Cannot transform xsetting Net/IconThemeName of type gchararray to type gint

gtk.gdk.screen_get_default().get_setting('gtk-icon-theme-name')

which I'm not sure if is related to the issue or not.

I've seen a similar bug report on Github.

Did anybody else have this issue? Maybe some system package upgrade broke an interface that all these applications previously used?

My laptop runs on Intel Skylake and GTX980M.

It appears that this is because of a recent kernel change, see here: https://ubuntuforums.org/showthread.php?t=2333398

See if you have kernel 4.4.0-34 (you can do so with the command 'uname -a'). I was unable to find if a bug has been filed for this, so you may want to do so.