Ubuntu – 13.10 Can’t Adjust Dell Laptop Backlight

13.10backlightdell

I have a Dell Studio 1558. When I originally installed 13.04 on it, I had to modify my /etc/default/grub with the following:

GRUB_CMDLINE_LINUX_DEFAULT="acpi_backlight=vendor dell_laptop.backlight=0 quiet splash"

Doing that made everything work, the keyboard brightness buttons, the OSD in the top right corner, and the brightness slider in System Settings. However, upon upgrading to 13.10, I once again am unable to adjust the backlight. This is also the case if I use either of the following:

GRUB_CMDLINE_LINUX_DEFAULT="acpi_backlight=vendor quiet splash"  
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

The backlight is stuck at a single brightness level, at a guess I think it's somewhere around 50%. The OSD still comes up if I push the keyboard buttons, but the bar only goes down one division from 100% and resets back to 100%, if I press decrease again. The slider in 'System Settings' does nothing.

Any help is greatly appreciated!

Best Answer

Doing both of the steps mentioned here fixed this issue with a Dell Studio 1558 and Ubuntu 13.10: http://ubuntuforums.org/showthread.php?t=2181534

Change /etc/default/grub

I used "sudo vim /etc/default/grub" but use whatever editor you're comfortable with but you will need to use sudo to edit it as the root user.

From:

GRUB_CMDLINE_LINUX="acpi_backlight=vendor"

To:

GRUB_CMDLINE_LINUX=""

Then run:

sudo update-grub

Add /usr/share/X11/xorg.conf.d/20-intel.conf

I used "sudo vim /usr/share/X11/xorg.conf.d/20-intel.conf" and then ran :set paste and hit i for insert and pasted in the contents.

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

Then reboot and login again and your function key with the brightness up/down should work again.

Related Solutions

Ubuntu – Cannot change backlight brightness Ubuntu 14.04

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

Open /etc/default/grub
```
sudo nano /etc/default/grub
```

to change the line

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash video.use_native_backlight=1"

then save and exit and
run
```
sudo update-grub
```
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.

Ubuntu – The brightness of laptop screen cannot be adjusted with either the buttons or the slider. Edit

I created a temporally bash script to adjust brightness level. Then I create 2 sortcuts at keyboard mapping settings to set up CTRL + Brightness UP or CTRL + Brightness Down with this script:

#!/bin/bash

# Step brightness value
STEP=2
# Max brightness value (defult 100)
MAX=100
# Min brightness value (defult 0)
MIN=0

COMMAND=$(xrandr --verbose | grep -i brightness | cut -f2 -d':' | tr -d "[:space:]")
ACTUAL=$(bc -l <<< $COMMAND*100 | cut -f1 -d'.')

while getopts ": u d" input
do
    case $input in
    u)  if [ $ACTUAL -lt $MAX ];then
                TOTAL=$(bc -l <<< $(($ACTUAL+$STEP))/100)
                $(xrandr --output DP-0 --brightness $TOTAL)
        fi;;
    d)  if [ $ACTUAL -gt $MIN ];then
                TOTAL=$(bc -l <<< $(($ACTUAL-$STEP))/100)
                $(xrandr --output DP-0 --brightness $TOTAL)
        fi;;
    ?)  printf "Usage: brightness [OPTION]\n"
        printf "Increase or decrease birghtness on Ubuntu Xorg.\n" 
        printf "WAYLAND MUST BE DISABLED\n\n"
        printf "  -u\t Increases brightness\n"
        printf "  -d\t Decreases brightness\n"
        exit 2;;
    esac
done

And in set custom shortcut I added this