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i am new to ubuntu and using Ubuntu 14.04 and installed nvidia graphics driver in my sony vaio E-series VpCEH25en but I cant change the brightness.

Alex Jones
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Ganapati chauhan
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2 Answers2

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To I'm just tried out the following command (As mentioned above)

  1. Ctrl+Alt+T: to open command prompt

  2. sudo gedit /etc/default/grub

  3. Find the line

    GRUB_CMLINE_LINUX_DEFAULT="quiet splash"

  4. Replaced this line with the following line

    GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux acpi_backlight=vendor"

  5. sudo update-grub

  6. reboot

It's definitely working on it.

hg8
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Kartik Chawda
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-2

Try this app ... it is handy one with out any overhead...

https://apps.ubuntu.com/cat/applications/brightness-controlleer/

Brightness Controller is the only GUI application for Linux that allows you to control brightness of your primary and secondary display from the same place. It is a software based dimmer. Released under GPL-3, Brightness Controller's source code is available.

**EDIT:TRY THIS ** Changing the /etc/default/grub file may work In terminal

sudo gedit /etc/default/grub

Find the line: 

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

and modify it to one of the following:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"

or

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linuxacpi_backlight=vendor" 
(try this if the first one doesn't work)

 Save and close gedit.

Then type 

 sudo update-grub

 Reboot your pc.

As from Ubuntu 13.10, needed one extra step for the problem to be solved.

Create an xorg.conf file in /etc/X11/ with the following contents:

Section "Device"
   Identifier      "Configured Video Device"
   Driver          "intel"
   Option          "Backlight"       "intel_backlight"
EndSection
#
Section "Monitor"
   Identifier      "Configured Monitor"
EndSection
#
Section "Screen"
   Identifier      "Default Screen"
   Monitor         "Configured Monitor"
   Device          "Configured Video Device"
EndSection

WARNING!! Getting the file wrong or if this configuration is not compatible with your hardware, might end up with an unbootable system!

In that case, you'll have to delete (or rename) the file, but to do so requires either booting from a liveUSB or liveDVD (the simplest way) or booting in recovery mode, making the Ubuntu partition rewritable and then delete the offending xorg.conf file.

vinrav
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