Cannot change backlight brightness Ubuntu 14.04

Solution 1:

I got a fix for my dell 5521 laptop, working for Ubuntu 14.04 but will work for kernels v3.13+.

1. Open /etc/default/grub

   sudo nano /etc/default/grub
   

2. to change the line

   GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
   

   to

   GRUB_CMDLINE_LINUX_DEFAULT="quiet splash video.use_native_backlight=1"
   

3. then save and exit and

4. run

   sudo update-grub
   

5. then reboot

The explanation is that ACPI adds its own back light control even if one is already present which is intel_backlight, adding this line forces CPI to use the Intel back light.

Solution 2:

For me, solution listed on bug report #1249219.

Basically it works creating the /usr/share/X11/xorg.conf.d/20-intel.conf file with the following lines:

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

Solution 3:

I created a simply script:

touch /usr/bin/brightness

The contents as follows:

#!/bin/bash
echo $1 | sudo tee /sys/class/backlight/intel_backlight/brightness

This allows you to then run the following from the command line:

brightness 100
brightness 4000

The values depend on your max brightness values which you can get by running:

cat /sys/class/backlight/intel_backlight/max_brightness 

Don't forget to make the script executable:

chmod +x /usr/bin/brightness

I opted not to change the permissions of the brightness file and keep the sudo part for security reasons.

Solution 4:

I have read A LOT of articles

Here is what I did, as I've been struggling with this for a long time...

Creating and modifying /usr/share/X11/xorg.conf.d/20-intel.conf file with the following lines...

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

...didn't work at all

I was using xbacklight option for some time, but it didn't satisfy me, as I knew it must be possible with Linux native way.

I've tried many GRUB options without effect, so I was googling again and again, coming back to solve this issue.

Today I came to the solution, which is following:

1. You need to kill your display manager, to create new Xorg.conf file (because it runs X server):
   • Press Ctrl+Alt+F1 (Dont panic, while your Window system is runing, you can go back with Ctrl+Alt+F7)
   • typesudo service lightdm stop and press Enter(e.g. gdm, kdm, xdm)
2. Create new Xorg configuration file
   • type X -configure and press Enter
   • type mv xorg.conf.new /etc/X11/xorg.conf and press Enter
3. Start X Server (you can do it all without GUI via command line, but I was more comfortable with this aproach):
   • typesudo service lightdm start and press Enter(e.g. gdm, kdm, xdm)
4. Modify Xorg.conf file
   • navigate to /etc/X11/xorg.conf and open Xorg.conf (in my case latest was xorg.conf.05312015) via leafpad (e.g. gedit, pluma)
   • search for Section "Device" and then for Driver (on my PC it said Driver "intel" by default, but it could be something else, so change it to intel)
   • add line Option "Backlight" "intel_backlight" after Driver "intel" (it doesn't really matter where, as long as it stays in Device Section)
   • save

5. Modify GRUB

   • sudo gedit /etc/default/grub (e.g. leafpad, pluma...)
   • set to GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=" (acpi_osi= did it for me, other options didn't work...)
   • in terminal type sudo update-grub and press Enter
   • or use GRUB customizer:

   sudo add-apt-repository ppa:danielrichter2007/grub-customizer sudo apt-get update sudo apt-get install grub-customizer

• press Save in upper left corner, which will update GRUB for you

  7. Restart and profit

Funny thing is, that code is exactly the same as in /usr/share/X11/xorg.conf.d/20-intel.conf, but that way it worked as expected!

Solution 5:

This worked for Acer 5830TG in Ubuntu 16.04 LTS

1. First make sure your system uses Intel Graphics card

   $ ls /sys/class/backlight
   intel_backlight
   

   At least intel_backlight should be mentioned

2. Now download and install Intel graphics driver and follow instructions.

3. On the grub configuration file /etc/default/grub modify the following line:

   GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
   

   to

   GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"
   

4. Then update grub

   sudo update-grub
   

5. Create and open the file /usr/share/X11/xorg.conf.d/20-intel.conf:

   gksudo gedit /usr/share/X11/xorg.conf.d/20-intel.conf
   

6. Add the following text:

   Section "Device"
           Driver      "intel"
           Option      "Backlight"  "intel_backlight"
           Identifier "card0"
   EndSection
   

7. Save and reboot.