Ubuntu – Unable to change brightness in settings

16.10backlightbrightnessdelllaptop

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.

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

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(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

Best Answer

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. `

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