How to reset external display?

Question

I am new to Swift programming, and I am having a little trouble understanding the definition of a module. Apple's Swift documentation states:

A module is a single unit of code distribution—a framework or application that is built and shipped as a single unit and that can be imported by another module with Swift’s import keyword.

The terminology above is confusing to me. Can someone explain in layman's terms of what a module in Swift is? Thank you for your patience :).

Solution 1

I'm still not sure how I got this to work, but I'll document the process in case anyone else has this same issue.

• Firstly I turned the laptop off
• Connect the display
• Turn on the laptop
• First time around this gave me a green screen again
• Press (in my case fnc+f1) to cycle the displays once
• This got me back to mirror mode

From mirror mode I could then use the display control panel to configure my displays into span, rather than just external.

Even though my Dell 2407WFP has a native resolution of 1920x1200 it seems that I can only output to it at 1680x1050. I think I might have a poor quality mDP -> DVI connector!

Solution 2

Clearly you can't see what's happening on screen when this is the case, right? If so, this is a bit of a long shot, but try punching in CTRL+ALT+F1, then type in your username, enter, your password, enter, and then try

xrandr --output LVDS1 --primary

Maybe that'll work. If not, your display probably isn't called LVDS1, in which case, disconnect from the external display and do:

xrandr -q

then replace 'LVDS1' above with whatever that command says your display is. It'll give you something along the lines of:

Screen 0: minimum 320 x 200, current 1024 x 768, maximum 1920 x 1080
LVDS connected 1280x800+0+0 (normal left inverted right) 304mm x 228mm
...

in which case, 'LVDS' is what you should use instead of 'LVDS1'. Hope that helps.