Plasma5 power management provider missing

[Anthony Jenkins]

Hi,

I recently built/installed KF5/Plasma5 as per the FreeBSD KDE wiki (git
repo from Sep. 23, 2017) and my KDE launcher menu "Leave" submenu has no
shutdown/reboot entries.  When I log into Plasma5, I get an error dialog
from the power management system:

KDE Power Management System could not be initialized.  The backend
reported the following error: No valid Power Management backend plugins
are available.  A new installation might solve this problem. Please
check your system configuration.

Searching $HOME/.xsession-errors for "PowerDevil" yields lines like the
following:

kded(1458) PowerDevil::Core::loadProfile: The profile  "AC" tried to
activate "BrightnessControl" a non existent action. This is usually due
to an installation problem or to a configuration problem. or simlpy the
action is not supported
kded(1458) PowerDevil::Core::loadProfile: The profile  "Battery" tried
to activate "DimDisplay" a non existent action. This is usually due to
an installation problem or to a configuration problem. or simlpy the
action is not supported
kded(1458) PowerDevil::Core::loadProfile: The profile  "Battery" tried
to activate "BrightnessControl" a non existent action. This is usually
due to an installation problem or to a configuration problem. or simlpy
the action is not supported
kded(1458) PowerDevil::Core::loadProfile: The profile  "AC" tried to
activate "DimDisplay" a non existent action. This is usually due to an
installation problem or to a configuration problem. or simlpy the action
is not supported
kded(1458) PowerDevil::Core::loadProfile: The profile  "AC" tried to
activate "BrightnessControl" a non existent action. This is usually due
to an installation problem or to a configuration problem. or simlpy the
action is not supported


If I sniff dbus messages while logging in and search those for "power",
I get this conspicuous line:

   string "The name org.kde.Solid.PowerManagement was not provided by
any .service files"

Disclaimer: this KF5/Plasma5 installation was attempted while I already
had KDE4 installed, so there's a good chance some KF5 system is trying
to talk to a KDE4 component or something.

Questions:
 - Anyone know what (else) I'm doing wrong?
 - I think this is a FAQ, but can KDE4 coexist with KF5?  I know several
KDE4 and KF5 ports have the same name in the normal and area51 ports
trees, respectively.  Any plans to rename those?
 - Where do I get a Solid.PowerManagement service provider, or what
could I port to FreeBSD to provide that?

Thanks,
Anthony Jenkins