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[Bug 1545266] Re: screen brightness slider has no effect


When I try to change the brightness, it is System Settings -> Brightness & Lock
I have identified the package as unity-control-center, not ubuntu docs as I reported erroneously at first.  
It is not a bug against ubuntu-docs that I know of.

** Package changed: ubuntu-docs (Ubuntu) => unity-control-center

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  screen brightness slider has no effect

Status in unity-control-center package in Ubuntu:

Bug description:
  Trusty Tahr 14.04 LTS, seems to be fully updated.

  The problem is: When I go to System Settings -> Brightness & Lock, the
  slider has no effect.  I can decrease the brightness slider to any
  level and the actual brightness of the monitors apparently does not
  change in any way.

  f.lux also has no effect.

  Also when i try to do

   echo 50 | sudo tee /sys/class/backlight/acpi_video0/brightness

  it has no effect

  (I learned why i can not do
  sudo echo 50 > /sys/class/backlight/acpi_video0/brightness, so that is good.)

  product: OptiPlex 7010 (OptiPlex 7010)

            description: CPU
            product: Intel(R) Core(TM) i3-3240 CPU @ 3.40GHz
            description: Host bridge
            product: Xeon E3-1200 v2/3rd Gen Core processor DRAM Controller
            vendor: Intel Corporation
               description: VGA compatible controller
               product: Xeon E3-1200 v2/3rd Gen Core processor Graphics Controller

  I would love to help provide some more help on my dual monitor setup.
  I found this documentation: https://wiki.ubuntu.com/X/Config/Resolution
  It says I should run $gnome-display-properties. Seems to be out of date.
  gnome-display-properties: command not found

  I guess it would be annoying to say it's a security vulnerability
  although if my screen isn't dim someone could more easily look through
  the window and see what I am typing on the screen.

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