second monitor won't wake up after power saving mode

[geo555]

Hi all,
the pc is a dell optiplex 7010 with i3 3220 and integrated graphics and linux mint 19.2
when it goes to power saving mode, the second monitor which is connected via display port won't wake up, unless I press the power on button.
I read in the forums that this was a bug in kernel 3.16 and it was fixed in later kernels, but it seems that is not fixed entirely.
Any ideas how to proceed?
thanks,
george

[gittiest personITW]

Hi,
Welcome to the forums.

Is that when you press the power button on the computer or on the monitor?

[geo555]

in the beginning both monitors work
when it goes to power saving mode, both monitos go to power saving mode.
when I press a key or the mouse, only the primary wakes up.
the second monitor wakes up only when I press the power on button (it only has one button that acts as joystic and everything else(lg))