Brightness key not working Ubuntu 16.04 LTS
I faced the same problem before on my laptop Lenovo z500 ideapad after searching i found this solution :
- open terminal
sudo nano "/etc/default/grub"-
append
acpi_backlight=vendorto theGRUB_CMDLINE_LINUX_DEFAULTline:GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor" - save and close
nano(Ctrl+X, then confirm saving changes) sudo update-grub- restart
If nothing changes , you can check the solutions of this question.