Comment 8 for bug 1753884

This happens to me periodically with Ubuntu 16.04.6 LTS, Kernel 4.14.114.

External HDMI 1080p TV nVidia GTX 970M driven
External HDMI 4K TV i915 Thunderbolt3 USB-C driven
Internal Dell 1080p LCD i915 driven

Method:

1) close laptop lid with power & systemd set to "do nothing"
2) external monitors will disconnect (no signal) and have to move mouse to reconnect.
3) select GUI suspend from external monitor
4) power off external screens after system suspends
5) power on external screens
6) open laptop lid to resume
7) about 20% of time login screen appears and all work is lost

If fixed in 17.10 would be nice to see backported to 16.04 as current plans for upgrade aren't until 20.04.