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Kubuntu recognizes the Fn + up/down but it only changes the brightness when it goes from 85% to 71% or viceversa. I want to know an easy way to change the screen brightness. I don't care if the method doesn't use the Fn key. I don't have installed the Nvidia drivers because kubuntu doesn't worked when I installed it and I had to reinstall kubuntu. I found this method but I don't know if ubuntu solutions work in kubuntu (let me know that too).

Software:

 - Release: `cat /etc/lsb-release | grep DISTRIB_RELEASE=` Kubuntu 14.04
 - KDE version `kde4-config -v`: 4.13.3
 - GRUB version: `apt-cache show grub | grep ersion` 0.97-29ubuntu66
 - There's no other OS

Hardware:

  • Samsung NP-R519 laptop
  • CPU make: lscpu

    Architecture:          i686
    CPU op-mode(s):        32-bit, 64-bit
    Byte Order:            Little Endian
    CPU(s):                2
    On-line CPU(s) list:   0,1
    Thread(s) per core:    1
    Core(s) per socket:    2
    Socket(s):             1
    Vendor ID:             GenuineIntel
    CPU family:            6
    Model:                 23
    Stepping:              10
    CPU MHz:               2100.000
    BogoMIPS:              4189.53
    L1d cache:             32K
    L1i cache:             32K
    L2 cache:              1024K 
    
  • GPU manufacturer and model: lspci | grep aphic

    Intel Corporation Mobile 4 Series Chipset PCI Express Graphics Port (rev 07)
    

    lspci -vnn | grep VGA -A 12

    01:00.0 VGA compatible controller [0300]: NVIDIA Corporation GT218M [GeForce G 105M] [10de:0a68] (rev a2) (prog-if 00 [VGA controller])
        Subsystem: Samsung Electronics Co Ltd Device [144d:c059]
        Flags: bus master, fast devsel, latency 0, IRQ 45
        Memory at cc000000 (32-bit, non-prefetchable) [size=16M]
        Memory at d0000000 (64-bit, prefetchable) [size=256M]
        Memory at ce000000 (64-bit, prefetchable) [size=32M]
        I/O ports at 2000 [size=128]
        [virtual] Expansion ROM at cd000000 [disabled] [size=512K]
        Capabilities: <access denied>
        Kernel driver in use: nouveau
    
    02:00.0 Network controller [0280]: Qualcomm Atheros AR9285 Wireless Network Adapter (PCI-Express) [168c:002b] (rev 01)
    Subsystem: Askey Computer Corp. Device [144f:7167]
    
  • RAM: sudo dmidecode --type 17 2 GB

1 Answer 1

0

The backlight control should work by default when using the open source nouveau driver. Instead, if you use the closed source nvidia driver, follow these instructions: Start "NVIDIA X Server Setting" from menu or type in a terminal:

sudo nvidia-settings

Select "X Server Display Configuration" from the left hand menu. Push button "Save to X Configuration File". Push button "Show preview...". Add the line

Option "RegistryDwords" "EnableBrightnessControl=1"

to Device section. It should look similar like this:

Section "Device"
Identifier     "Device0"
Driver         "nvidia"
VendorName     "NVIDIA Corporation"
BoardName      "GeForce GT 330M"
Option "RegistryDwords" "EnableBrightnessControl=1"
EndSection

Uncheck "Merge with existing file".

Save the file to /etc/X11/xorg.conf.

Reboot and check if backlight control works.

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