The issue seems to be fixed in 14.04.4 (64bit). Just installed it fresh on another Lenovo S21e-20 (same model as previously), and brightness control now works as expected.
-- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to systemd in Ubuntu. https://bugs.launchpad.net/bugs/1523041 Title: Lenovo S21e: brightness keys seem inversed Status in systemd package in Ubuntu: Incomplete Bug description: Fresh install of Xubuntu Trusty (14.04.3 64bit) on a Lenovo S21e. The brightness +/- keys work, but their function seems to be reversed: - minus makes it brighter - plus makes it darker Additionally, the screen goes completely off (no backlight) when reaching the lowest or highest brightness step. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1523041/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : email@example.com Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp