[xubuntu-users] xubuntu 19.04, laptop display won't turn back on

[Chris Green]

I have recently upgraded my Thinkpad T470 laptop to xubuntu 19.04, I'm
not sure if this problem is a result of the upgrade or not.

I have the xfce Power Manager set up to turn the display off after 15
minutes or so idle.  The problem is that the display doesn't restart on
keyboard or mouse activity.  This has always worked perfectly with
previous versions of xubuntu (at least back to 18.04 but probably
further).

The system is still running, I can ssh into it and reboot successfully
when the display has turned off.

I have 19.04 on a desktop machine with the same setup and that works
OK, the display comes back on when you jiggle the mouse or hit the
keyboard,

I don't run a screensaver at all.

How can I diagnose/fix this problem?

-- 
Chris Green