I have a Dell Studio 1558 with keyboard backlighting. My problem has to do with the backlight no longer turning back on once it has turned off.
Historically, I have had to edit /etc/dbus-1/system.d/org.freedesktop.UPower.conf and comment out the following two lines for keyboard backlighting to work:
Quote:
<allow send_destination="org.freedesktop.UPower"
send_interface="org.freedesktop.UPower.KbdBacklight"/>
Recently I discovered that this file had been moved to /usr/share/dbus-1/system.d/org.freedesktop.UPower.conf, where I repeated my edit, but have still been having problems that once my keyboard backlight turns off, it won't turn back on by keyboard or touchpad activity.
Further investigation showed that the contents of the file start_triggers in /sys/class/leds/dell::kbd_backlight (also found in /sys/devices/platform/dell-laptop/leds/dell::kbd_backlight) are set to "-keyboard -touchpad".
When I edit the file to contain "+keyboard +touchpad" things work for a while. When the keyboard backlight turns off, keyboard or touchpad activity turns it back on.
My problem is that something keeps changing the file contents back to "-keyboard -touchpad", which leaves me having to turn the keyboard backlight back on using the function key - something hard to do in the dark!
When I do turn on the keyboard backlight with the Fn-F6 function key (which is only supposed to be used to changing brightness), the start_triggers file is again modified by the system to "+keyboard +touchpad", but this goes away after a while with the contents reverting to "-keyboard -touchpad".
I've not determined the exact parameters of when the keyboard backlight is disabled, whether it's just a matter of time, or letting the laptop sleep or something else. And I have no idea what process is playing with start_triggers.
Any help if getting this back under control will be greatly appreciated.