1

NOT A POSSIBLE DUPLICATE: My question is not the same as Can't change brightness in Ubuntu 16.04 LTS because I have tried most of the solutions there and they didn't work.


Whenever I try to change the brightness using system settings -> brightness and lock -> brightness slider, moving the slider has no effect and when I close system settings, the slider goes back to the full brightness position.

enter image description here (move the brightness slider to minimum [has no effect] and close system settings)

enter image description here (reopen brightness and lock and the slider is back to full brightness)

The buttons on the keyboard have the same effect.

lspci:

00:02.0 VGA compatible controller: Intel Corporation Haswell-ULT Integrated Graphics Controller (rev 0b)
00:03.0 Audio device: Intel Corporation Haswell-ULT HD Audio Controller (rev 0b)
00:14.0 USB controller: Intel Corporation 8 Series USB xHCI HC (rev 04)
00:16.0 Communication controller: Intel Corporation 8 Series HECI #0 (rev 04)
00:1b.0 Audio device: Intel Corporation 8 Series HD Audio Controller (rev 04)
00:1c.0 PCI bridge: Intel Corporation 8 Series PCI Express Root Port 1 (rev e4)
00:1c.2 PCI bridge: Intel Corporation 8 Series PCI Express Root Port 3 (rev e4)
00:1c.3 PCI bridge: Intel Corporation 8 Series PCI Express Root Port 4 (rev e4)
00:1d.0 USB controller: Intel Corporation 8 Series USB EHCI #1 (rev 04)
00:1f.0 ISA bridge: Intel Corporation 8 Series LPC Controller (rev 04)
00:1f.2 SATA controller: Intel Corporation 8 Series SATA Controller 1 [AHCI mode] (rev 04)
00:1f.3 SMBus: Intel Corporation 8 Series SMBus Controller (rev 04)
06:00.0 Network controller: Qualcomm Atheros QCA9565 / AR9565 Wireless Network Adapter (rev 01)
07:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8101/2/6E PCI Express Fast/Gigabit Ethernet controller (rev 07)

lspci -nnk | grep -A2 VGA:

00:02.0 VGA compatible controller [0300]: Intel Corporation Haswell-ULT Integrated Graphics Controller [8086:0a16] (rev 0b)
  Subsystem: Dell Haswell-ULT Integrated Graphics Controller [1028:0651]
  Kernel driver in use: i915

ls /sys/class/backlight/:

dell_backlight  intel_backlight
  • Have you tried using the buttons on the keyboard? – Antivistv2 Jan 13 '17 at 3:34
  • They have the same effect. – nom Jan 13 '17 at 3:36
  • 1
    Possible duplicate of Can't change brightness in Ubuntu 16.04 LTS – Jim Jan 13 '17 at 3:40
  • Is your Ubuntu a fresh install? or you've just upgraded? Mine is fresh install and I don't have problems in it – Antivistv2 Jan 13 '17 at 3:41
  • It is a fresh install. – nom Jan 13 '17 at 3:44
1

Change the files /sys/class/backlight/xxx/brightness manually, where xxx are replaced by dell_backlight and intel_backlight, to figure out which interface is responsible for your backlight control.

To change the value in /sys/class/backlight/xxx/brightness open a terminal and run:

sudo bash -c "echo 5 > /sys/class/backlight/xxx/brightness;"

Then create /etc/X11/xorg.conf if not exists and add:

Section "Device"
    Identifier  "Card0"
    Driver      "intel"
    Option      "Backlight"  "xxx"
EndSection

After edit /etc/X11/xorg.conf reboot your system and let me know if it works. `

1

You can run this command that works for all graphics cards:

for gcard in /sys/class/backlight/* ; do sudo bash -c "echo 5 > $gcard/brightness" ; done

If your account has sudo privileges you can simply add the above oneliner to your ~/.bashrc and be done with it.

Update: However this may not work when you lock/unlock your laptop. In that case you can write a script let's say with the name ~/.brightnesss_adjuster.sh (and make it exectuable) with this content:

#!/bin/bash
dbus-monitor --session "type='signal',interface='org.gnome.ScreenSaver'" | ( while true
do read X
if echo $X | grep "boolean false" &> /dev/null; then
    for gcard in /sys/class/backlight/* ; do sudo bash -c "echo 5 > $gcard/brightness" ; done
fi
done )

And then add this line to your ~/.bashrc:

# brightness set up
~/.brightness_adjuster.sh &

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.