Comment 5 for bug 1510344

Jan Henke (jhe) wrote :

This is probably related to the change introduced in Linux 4.1. The Dell keyboard driver can now control various settings about the keyboard back-light and exposes control devices in /sys to change these settings.

Commit: 6cff8d60aa0aba5583ecda09984dbcb2f24cc28d (https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=6cff8d60aa0aba5583ecda09984dbcb2f24cc28d)

For some reason the backlight is set to on in certain conditions, ignoring the previous user setting.