What do I need to do to get my laptop screen backlight brightness controls to work? I currently have Ubuntu 13.04 and a Dell Studio 1558.After reading these two links:https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1007765http://ubuntuforums.org/showthread.php?t=2061712I attempted the following, I change the permissions (since I was having errors editing the files)sudo chmod a+w /sys/class/backlight/intel_backlight/brightnessAnd then I overwrote the file with 1000 (appears max_brightness is 4882)sudo echo 1000 > /sys/class/backlight/intel_backlight/brightnessAnd lo and behold, my screen dimmed. I've tweaked it before, I'm not sure exactly how, and I don't know why I had to change the permissions on the file again, if I did it that way before.How can I adjust brightness with the standard keys?
How do I get my laptop screen backlight brightness controls to work?
backlight
xbacklight$ xbacklight +30% # increases brightness by 30 percent$ xbacklight -30% # decreases brightness by 30 percentdbus way$ dbus-send --session --print-reply \      --dest=org.gnome.SettingsDaemon \      /org/gnome/SettingsDaemon/Power \      org.gnome.SettingsDaemon.Power.Screen.SetPercentage \      uint32:<percentage>ExampleSet brightness to 30%:$ dbus-send --session --print-reply \      --dest=org.gnome.SettingsDaemon \      /org/gnome/SettingsDaemon/Power \      org.gnome.SettingsDaemon.Power.Screen.SetPercentage \      uint32:30 OrTo decrease brightness by a step (~7)  $ dbus-send --session --print-reply \      --dest=org.gnome.SettingsDaemon \      /org/gnome/SettingsDaemon/Power \      org.gnome.SettingsDaemon.Power.Screen.StepDownTo increase brightness by a step (~7)  $ dbus-send --session --print-reply \      --dest=org.gnome.SettingsDaemon \      /org/gnome/SettingsDaemon/Power \      org.gnome.SettingsDaemon.Power.Screen.StepUpIf it says as follows your OS may be too old. Then use xdotool:Error org.freedesktop.DBus.Error.UnknownMethod: Method SetPercentage with signature u on interface org.gnome.SettingsDaemon.Power.Screen doesn't existxdotoolIncrease brightness:$ xdotool key XF86MonBrightnessUpDecrease brightness:$ xdotool key XF86MonBrightnessDown