Description of problem:
I have Lonevo x240 in dock with two external monitors which do not want to switch off, in gnome-shell it works.

If I use xset dpms force off, it works but after some time (a minute or earlier) it became on again.

Version-Release number of selected component (if applicable):
$ rpm -qa mate\*
mate-desktop-1.14.1-2.el7.x86_64
mate-disk-usage-analyzer-1.14.1-1.el7.x86_64
mate-power-manager-1.14.0-1.el7.x86_64
mate-desktop-libs-1.14.1-2.el7.x86_64
mate-settings-daemon-1.14.1-1.el7.x86_64
mate-control-center-filesystem-1.14.1-1.el7.x86_64
mate-terminal-1.14.1-1.el7.x86_64
mate-panel-1.14.2-1.el7.x86_64
mate-dictionary-1.14.1-1.el7.x86_64
mate-backgrounds-1.14.0-1.el7.noarch
mate-menus-libs-1.14.0-1.el7.x86_64
mate-notification-daemon-1.14.1-1.el7.x86_64
mate-icon-theme-1.14.0-1.el7.noarch
mate-system-monitor-1.14.1-1.el7.x86_64
mate-screensaver-1.14.1-1.el7.x86_64
mate-system-log-1.14.1-1.el7.x86_64
mate-menus-1.14.0-1.el7.x86_64
mate-polkit-1.14.0-1.el7.x86_64
mate-themes-3.14.3-1.el7.noarch
mate-menus-preferences-category-menu-1.14.0-1.el7.x86_64
mate-utils-common-1.14.1-1.el7.noarch
mate-session-manager-1.14.1-1.el7.x86_64
mate-user-guide-1.14.0-1.el7.noarch
mate-media-1.14.1-1.el7.x86_64
mate-search-tool-1.14.1-1.el7.x86_64
mate-calc-1.8.0-1.el7.x86_64
mate-control-center-1.14.1-1.el7.x86_64
mate-screenshot-1.14.1-1.el7.x86_64
mate-panel-libs-1.14.2-1.el7.x86_64
mate-applets-1.14.0-1.el7.x86_64