Йога яркость Thinkpad X1 OLED

Я запускаю Ubuntu 17.10 с GNOME (Уэйленд) на Lenovo X1 Yoga OLED.

Я верю этой конкретной установке Ubuntu, начатой с Ubuntu 16.04 несколько лет назад. Я выполнял GNOME в системе, так как это было сначала установлено. - Это означает, что я мог бы иметь некоторое древнее переопределение в запасе в своей системе, о которой я просто забыл.

Проблема: Я получаю много сообщений об ошибках от гнома-демона настроек в моем журнале:

feb 23 13:04:32 kul org.gnome.SettingsDaemon.Power.desktop[1741]: Error executing command as another user: Not authorized
feb 23 13:04:32 kul org.gnome.SettingsDaemon.Power.desktop[1741]: This incident has been reported.
feb 23 13:04:33 kul pkexec[408567]: gdm: Error executing command as another user: Not authorized [USER=root] [TTY=unknown] [CWD=/var/lib/gdm3] [COMMAND=/usr/lib/gnome-settings-daemon/gsd-backlight-helper --set-brightness 843]
feb 23 13:04:33 kul org.gnome.SettingsDaemon.Power.desktop[1741]: Error executing command as another user: Not authorized
feb 23 13:04:33 kul org.gnome.SettingsDaemon.Power.desktop[1741]: This incident has been reported.
feb 23 13:04:33 kul pkexec[408571]: gdm: Error executing command as another user: Not authorized [USER=root] [TTY=unknown] [CWD=/var/lib/gdm3] [COMMAND=/usr/lib/gnome-settings-daemon/gsd-backlight-helper --set-brightness 843]
feb 23 13:04:33 kul org.gnome.SettingsDaemon.Power.desktop[1741]: Error executing command as another user: Not authorized
feb 23 13:04:33 kul org.gnome.SettingsDaemon.Power.desktop[1741]: This incident has been reported.
feb 23 13:04:34 kul pkexec[408575]: gdm: Error executing command as another user: Not authorized [USER=root] [TTY=unknown] [CWD=/var/lib/gdm3] [COMMAND=/usr/lib/gnome-settings-daemon/gsd-backlight-helper --set-brightness 758]
feb 23 13:04:34 kul org.gnome.SettingsDaemon.Power.desktop[1741]: Error executing command as another user: Not authorized
feb 23 13:04:34 kul org.gnome.SettingsDaemon.Power.desktop[1741]: This incident has been reported.
feb 23 13:04:35 kul pkexec[408579]: gdm: Error executing command as another user: Not authorized [USER=root] [TTY=unknown] [CWD=/var/lib/gdm3] [COMMAND=/usr/lib/gnome-settings-daemon/gsd-backlight-helper --set-brightness 783]
feb 23 13:04:35 kul org.gnome.SettingsDaemon.Power.desktop[1741]: Error executing command as another user: Not authorized
feb 23 13:04:35 kul org.gnome.SettingsDaemon.Power.desktop[1741]: This incident has been reported.
feb 23 13:04:35 kul pkexec[408585]: gdm: Error executing command as another user: Not authorized [USER=root] [TTY=unknown] [CWD=/var/lib/gdm3] [COMMAND=/usr/lib/gnome-settings-daemon/gsd-backlight-helper --set-brightness 800]
feb 23 13:04:35 kul org.gnome.SettingsDaemon.Power.desktop[1741]: Error executing command as another user: Not authorized
feb 23 13:04:35 kul org.gnome.SettingsDaemon.Power.desktop[1741]: This incident has been reported.

Я отключил/включил "Автоматическую яркость" управление в панели Settings, это, кажется, ничего не изменяет.