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I have a problem adjusting my laptop's brightness. This is a hardware problem but I can solve it with ccsm, but other programs do not work for me, e.g., xgamma, etc.

Now I am running Fedora 15 and Gnome3 I cannot use compiz: is there another solution?

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migrated from askubuntu.com Jul 17 '11 at 13:22

This question came from our site for Ubuntu users and developers.

I think this problem is about Gnome 3, not Fedora – fronthem Jul 17 '11 at 5:44

Try editing /etc/default/grub to set GRUB_CMDLINE_LINUX to acpi_osi=Linux and then running update-grub. I found it in this Ubuntu Forums post; it worked on my Acer Aspire, but I'm not sure if it works on other computers

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how can i config grub in fedora dont hav /etc/default/grub – fronthem Jul 18 '11 at 19:41
This solution worked on my HP Envy 17 2001g while running Crunchbang Statler with Kernel 3.2... just saying, if anyone comes across here :D – Marco May 28 '12 at 0:45

I was with the same problem in my laptop, a Dell Vostro 3300 with Ubuntu 11.04, this configuration solved my problem.

  • Edit /etc/Xorg/xorg.conf to add the following line under Section "Device":

    Option "RegistryDwords" "EnableBrightnessControl=1"
  • Edit /etc/default/grub and addacpi_osi=Linuxto theGRUB_CMDLINE_LINUX` setting, i.e.


    then run sudo update-grub and reboot.

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Please do more than just link to an answer. At the very least summarize the answer or copy the most important parts of the config you reference into your answer. – Caleb Jul 18 '11 at 13:30
edit /etc/default/grub to change the line into: GRUB_CMDLINE_LINUX="acpi_osi=Linux" /etc/default/grub in fedora not found. How can i config grub? – fronthem Jul 19 '11 at 11:46
up vote 2 down vote accepted

OK, I found a way to solve this problem on Acer with Fedora 15 (thanks to Fedora forums and answers here):

  1. Update the BIOS to the lastest version.
  2. Edit /etc/Xorg/xorg.conf to add the following line under Section "Device":

    Option "RegistryDwords" "EnableBrightnessControl=1"
  3. Edit /boot/grub/grub.conf to add the parameters acpi_backlight=vendor acpi_osi=Linux on the kernel command line (at the end of the line that looks like linux /vmlinuz root=/dev/sda1 ro).

  4. Reboot.
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I only had to add

Option "RegistryDwords" "EnableBrightnessControl=1"

to /etc/Xorg/xorg.conf. When adding the parameters (which are mentioned in other posts) to /etc/default/grub, the brightness adjustment did still work but displaying the brightness level when changing the brightness did not change any more.

Im running Ubuntu 11.10 and Gnome3, on a Lenovo T420s

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