I am using Sony Vaio E Series VPCEH25EN laptop.
I installed ubuntu 12.04 64 bit version and I couldn't change my brightness level.
Always it is showing max brightness,
I tried to change by using echo 0 | sudo tee /sys/class/backlight/acpi_video0/brightness
command.
When I run the above cmd it showing output as 0 but there is no change in brightness level. please help out how to change brightness levels.
Best Answer
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 likeAlso you can try with xdotool