I'm running Manjaro with Gnome 3.26. I'm having an annoying issue with my laptop. Every time it goes to sleep and wakes again, the external display does not come back. I am forced to disconect and reconnect the HDMI cable. I've tried both the 4.9 and 4.14 kernels with no change.
The laptop is the Xiaomi Notebook Pro and has an nVidia MX150. I'm using the video-hybrid-intel-nvidia-bumblebee driver from Manjaro Settings Manager.