In a HP sleekbook 15 laptop I managed to install NVidia driver and also quick switch graphics is working. When NVidia card is active I can adjust the brightness using keyboard but when intel card is active the adjust is not possible. I have to mention that I have followed next advice "Edit /usr/share/X11/xorg.conf.d/20-intel.conf as root. Enter the following text:

          Section "Device"
          Identifier "card0"
          Driver "intel"
          Option "Backlight" "intel_backlight"
          BusID "PCI:0:2:0"

          EndSection                "

but still doesnt work for intel graphic card.

Someone can help? Thank you!

  • Thanks! The solution of user "Gtx" worked for my LG P530-K.AE23B. Changing brightness was impossible since 13.04 version.
    – xapilla
    Apr 30, 2014 at 18:45

1 Answer 1


Edit the /etc/default/grub file

sudo gedit /etc/default/grub

or sudo nano /etc/default/grub

find this line:


add acpi_backlight=vendor to the value so it looks like this:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"

then apply grub configs: sudo update-grub

and reboot

This worked for my HP ProBook.

Solution found here: http://www.techjail.net/solved-brightness-problem-in-ubuntu-12-04-precise-pangolin.html

  • Hi! Thank you for your answer. I tried your suggestion but did not work for me. After "sudo update-grub" I restarted and after this I was not able to switch between graphic cards and also NVidia Prime profile it is lost. When I made the change back then I have the initial situation, that means I am able to switch between cards and adjusting of brightness by keyboard it is possible only for NVidia card. For Intel card it is possible only from System settings--> Brightness&Lock.
    – Marius123
    Apr 19, 2014 at 16:47
  • ooops! Sorry... Seems that it is working only after rebooting the system two times. A little strange: I followed again your advice, than I rebooted (after first reboot I lost the Prime Profile and was not possible to switch between cards) and then reboot again without doing anything else. After second reboot the prime profile was available, was possible to switch between cards and also possible to adjust brightness by keyboard for both cards. Then Iagain rebooted few times and seems that it is ok... Thank you!
    – Marius123
    Apr 19, 2014 at 16:56
  • It worked for me. I have HP ProBook 4430s. Thanks :)
    – ajay
    Apr 26, 2014 at 16:21
  • It didn't work for my Dell Inspiron 15r May 14, 2014 at 9:53
  • Works perfectly for HP ProBook 4440. Thank you.
    – Haridas N
    Dec 29, 2014 at 12:01

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