Back light staying on when screen blanks

[Colin Law]

I have an issue since recent updates (on Precise) where my laptop
backlight stays on when the screen is blanked following a period of
inactivity.  The screen goes blank but the backlight is still on,
which rather defeats the object of the exercise.  This is with Intel
graphics.  I can't find a bug report other than [1] which maintains
that the issue is to do with nvidia.  I don't know what package to
report the bug against, suggestions would gratefully received.

Colin

[1] https://bugs.launchpad.net/ubuntu/+source/nvidia-graphics-drivers-updates/+bug/931040