16.10 - Backlight intel + acpi conflict - Ask Ubuntu

after ubuntu studio upgrade 16.04 16.10 when decrease screen brightness, backlight flickers rapidly. can use 2 highest levels brightness. installed brightness-indicator troubleshooting still use f5 , f6 keys.

in /sys/class/backlight/ have acpi_video0 , intel_backlight folders. guessed there conflict these 2 folders contain same files. tried rename acpi_video0 in acpi_video0.back, it's impossible modify files, permission denied if change permissions.

the cause of problem may have come manipulation did before upgrade. followed tutorial:

function keys require grub edit

modify grub using command:

gksudo gedit /etc/default/grub 

change grub_cmdline_linux_default="quiet splash" grub_cmdline_linux_default="quiet splash acpi_osi="

update grub command:

sudo update-grub 

then reboot

this take care of function keys except events brightness keys...

brightness keys

create config file using command:

gksudo gedit /usr/share/x11/xorg.conf.d/20-intel.conf 

place following file contents:

# begin file contents section "device" identifier "card0" driver "intel" option "backlight" "intel_backlight" busid "pci:0:2:0" endsection # end file contents: 

to give more information configuration, past extract of /etc/default/grub

grub_default=0 #grub_hidden_timeout=0 grub_hidden_timeout_quiet=true grub_timeout=10 grub_distributor=`lsb_release -i -s 2> /dev/null || echo debian` grub_cmdline_linux_default="quiet splash acpi_osi= pci=noaer" grub_cmdline_linux=""