Try below,
execute gksu 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.
This is for setting brightness manually after doing the above steps.
Try following for paths shown by ls /sys/class/backlight/*/brightness and replace accordingly.
example paths will be like
/sys/class/backlight/acpi_video0/brightness
- For the above path Get the maximum brightness:
cat /sys/class/backlight/acpi_video0/max_brightness
Try a lower value to set the brightness, say output is 16 so I will try with half of it
echo 8 | sudo tee /sys/class/backlight/acpi_video0/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/acpi_video0/brightness
exit 0
Best Answer
I tried the
xrandr --output VGA1 --brightness 0.9command from Lubuntu running on my netbook(Samsung NC110, Intel Atom N455 1.66Ghz RAM 2GB). This could only produce terminal's retort of “xrandr: Need crtc to set gamma on.”Afterwards I kept searching on the web and found out about the “
xbacklight -inc XX” command, which solved my problem. The XX stands for % you want increased(-inc) or decreased(-dec), so the actual command that I used was xbacklight -dec 40 since my monitor was too bright.P.S.- I still would like to know how to give others with answers written feedback (other than just clicking on a "Yes" or "No") on this site, as with most of the Linux realm, user friendliness is a luxury rarely found. Currently I only understand how to provide answers.