turn of a mintor that doesn't support DPMS

[张韡武]

Hello. Recently my monitor of the FreeBSD host is broken that it ignore
power management. E.g. if the monitor should be powered-off on 15 minute
of inactive, it does not power-off, but simply show blank screen. Also
the power button on the screen have no effect (press this button, screen
still on). This is also tested with Linux. The DPMS feature should have
been broken.

However it turns out a KVM switch can effectively turn off this monitor,
if I switch to a console (KVM pair) that connect to no computer, the
monitor turns off.

Is there a software-solution to turn off the Monitor when its DPMS not
working?