I am facing a problem with display brightness in Ubuntu or other versions of Linux. Running a Linux distro as live or HDD installation or inside the installation, display brightness is automatically set to the highest value, I'm unable to decrease it, this is an annoying problem at night.
I have tried about 25 different Linux Distros in my laptop another 3 laptops of friends but the same problem, no problem with the desktop as the monitor has its own brightness control switch.
My laptop is Acer 5830TG, i5 2410M @ 2.3 GHz, ram-3gb, HDD-640gb @5400 rpm, NVIDIA GT540M,
chipset-Intel HM65. OEM os- windows7 Home Premium.
I have tried the Fn+< (left arrow key) as in windows, Ubuntu is showing that brightness is decreased but not really, display brightness is same.
Also tried Ubuntu display brightness applet.
And at Terminal~$ sudo setpci -s 00:02.0 F4.B=**
where **
is two digit hex value, 00:02.0 is internal display adapters(Intel HD 3000) hardware address(lspci | grep VGA).
Nothing happened, display brightness remained the same.
Best Answer
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
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