The brightness buttons and the brightness control in system settings in Ubuntu 15.10 have suddenly stopped working. They were working fine at first(after I upgraded from 15.04). I have no Xorg.conf
file but I believe that file is no longer required.
Note that xbacklight -dec 10
(Xbacklight package installed) command works and I am able to reduce brightness through the command, however the Brightness buttons(F11,F12) fail to respond.Also I am unable to adjust brightness through system settings(gnome-control-center). I have tried making changes to /etc/default/grub but they have no effect.
Command: cd /sys/class/backlight/
output : intel_backlight
edit 1:
This question is not a duplicate of "Why don't my Fn keys work for brightness or media after upgrading?" ,since my keys are mapped to the correct buttons. The problem did not occur after the a distro upgrade and the also, the solution suggested did not work.
command : acpi_listen
output :
video/brightnessdown BRTDN 00000087 00000000
video/brightnessup BRTUP 00000086 00000000