Cannot change screen brightness in Ubuntu
I just reconfigured Ubuntu 14.4 in my Latitude 3540 model laptop, ran software update to latest patches available for Ubuntu 14, for wifi I just installed from additional hardware searching for available wireless adapter. everything seems to be working fine,
except brightness control by keyboard shortcut… I was stuck there and could get a solution after some research.
Open a terminal (Ctrl + Alt + T).
$ sudo nano /etc/default/grub
Will edit the grub file here
Around the 11th line, find something like: GRUB_CMDLINE_LINUX_DEFAULT=”quiet splash”.
Change it to GRUB_CMDLINE_LINUX_DEFAULT=”quiet splash acpi_backlight=vendor”
Save the file by Ctrl+O followed by Ctrl+X.
Then run in terminal
$ sudo update-grub
Reboot the machine
$ sudo shutdown -r now
now you can see brightness control through keyboard is working now.
Hope it helps.
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