I experienced a problem connecting a projector via VGA yesterday. I was trying to sort out the resolution and one thing I tried was "mirror displays" but that wasn't what I wanted so I clicked the revert button. The screens both became confused, with the whole screen (including the reversion dialogue) displayed multiple times (tiled) but it never finished reverting. The mouse pointer was still there and movable, but nothing on screen could be interacted with and nothing I tried on the keyboard (e.g. restart Cinnamon, force log-out, open the Start menu) had any effect. I had to power down the machine forcibly.
This morning I succeeded in replicating the issue using a VGA-connected monitor. The result was the same. I thought I would video the process on my phone to post here, but when I reconnected the "offending" monitor it froze the display in a similar way to when the original issue occurred and again I had to forcibly power of my machine.
Is there somewhere I can look to see what went wrong?
Is there a way I can reset my external monitors?
I'm currently connected to another monitor via mini display port and that's fine - although I daren't make any changes to the settings!
The process that originally broke things was:
- Connect monitor via VGA.
- Open display settings.
- Drag the monitor to above the laptop's monitor and Apply.
- Tick "Mirror displays" and Apply
- Click the Revert button
- Screen doesn't revert properly and becomes unresponsive except for the mouse pointer being movable.