The solution for me was to edit the /etc/X11/xorg.con
f file. It's a problem with the graphics driver not the keymap.
Open the file for editing and add the line
Option "RegistryDwords" "EnableBrightnessControl=1"
in the Section "Device"
section as shown below.
Section "Device"
Identifier "Device0"
Driver "nvidia"
VendorName "NVIDIA Corporation"
Option "RegistryDwords" "EnableBrightnessControl=1"
Option "NoLogo" "True"
EndSection
Your system has nvida chips. So please install driver from Addtional Drivers
(press Super / Win, and search for it). Reboot and see if it solves the problem.
If above not working try following (but don't uninstall the driver)
execute sudo gedit /etc/default/grub
Change this line
GRUB_CMLINE_LINUX_DEFAULT="quiet splash"
to something like below
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux acpi_backlight=vendor"
Execute sudo update-grub
and reboot . See if brightness keys are working.
It is still possible ubuntu won't remember your brightness settings. So you have to change brightness each time.
Please let us know the result as many sony users are facing this problem.
Update: This is for setting brightness manually.
Try following for path shown by ls /sys/class/backlight/*/brightness
and replace accordingly.
Get the maximum brightness:
cat /sys/class/backlight/intel_backlight/max_brightness
Try a lower value to set the brightness, say output is 2048 so I will try with half of it
echo 1024| sudo tee /sys/class/backlight/intel_backlight/brightness
If this works, make this happen in each login automatically by doing the following
sudo gedit /etc/rc.local
Enter this line just before exit 0
. It should look like
echo YOUR_VALUE_HERE > /sys/class/backlight/intel_backlight/brightness
exit 0
Also you can try with xdotool
Best Answer
the only way to change brightness is to use this command
sudo su
echo 150 > /sys/class/backlight/intel_backlight/brightness
all other solution does not work at the moment. this is not my work around. i dont remember where i got this but it works and hats off to the person who gave this workaround :)
Using Ubuntu 13.10 64Bit Wubi on Lenovo Z570