Display on HDMI doesn't wake up

I found a way to wake up the monitor. It is not ideal but much better than restarting X server or rebooting. I created a simple shell script which forces graphics mode to be reset.

#!/bin/bash
xrandr --output HDMI2 --primary --mode 2560x1440

or a simpler one

#!/bin/bash
xrandr --output HDMI2 --auto

Then I assigned a hot key combination to invoke my script. This way the monitor wakes up but only on specific key press vs any key or mouse event.

I will wait for a better answer before accepting my own answer. I am still hopeful that somebody knows a way to fix the actual problem.

UPDATE 2018-01-12 I upgraded kernel from the default LTS version to the latest (https://wiki.ubuntu.com/Kernel/LTSEnablementStack) and the monitor now behaves as it is supposed to. Thanks to @Ellis Whitehead for pointing out it could be a problem in the kernel implementation.