1

I'm running Ubuntu Gnome 14.04 on a Thinkpad X1 Carbon. When I unplug the HDMI cable, my brightness comes down to zero, and I can't increase it again.
With Fn + F9 as I normally would.

storm
  • 5,013
Costa Michailidis
  • 5,190

1 Answers1

2

I faced the same problem before on my laptop Lenovo z500 ideapad after searching i found this solution :

 1. open terminal 
 2. sudo gedit "/etc/default/grub"
 3. append "acpi_backlight=vendor" to GRUB_CMDLINE_LINUX_DEFAULT
 4. GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"
 5. save and close gedit
 6. sudo update-grub
 7. restart

If nothing changes , you can check the solutions of this question.

Mohamed Slama
  • 1,849