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I regularly use an external monitor with my laptop, so when I use it, I usually have the laptop screen disabled when the monitor is connected, and this seems to cause problems when the monitor is disconnected. If the monitor is connected while the laptop screen is disabled, I can't get the X session to show up at all:

  • I can Ctrl+Alt+F1 to open a terminal, and that works fine..
  • ..but Ctrl+Alt+F7 does nothing. The display is blank, and stays blank. The same thing happens whether I put the computer to sleep with the monitor connected, or if I disconnect while the computer is still awake.

Rebooting the computer fixes the issue, as does killing Xorg and starting it again, but both of those are sub-optimal since I lose my current session. I'm currently using the open source graphics driver (xserver-xorg-video-ati).

This question looks like it might answer my question, but unfortunately hwinfo is no longer available in the apt repository.

  • Is there a way with current tools to automatically detect when the external monitor is disconnected and switch to the laptop display?
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  • No matter what device, you should never simply remove it while in use. this could cause irreversible damage to the device in question. Even if you find a way to fix this problem i highly recommend manually switching the active monitor in in system settings before unplugging the monitor Apr 16, 2014 at 21:14
  • While I have never seen removing a monitor cause any damage, it doesn't apply in this case all the time. It happens even when the computer and monitor are both asleep and the monitor is disconnected.
    – Ryan
    Apr 16, 2014 at 21:17
  • on that note i will say that it sounds like ubuntu doesnt realize the moniter is no longer present. This could most likley be fixed by restarting your windowing system. The process would be specific to your windowing system, and i couldnt really tell you how to do so... make it a question and ill +1 it =) and like aquaherd said... 14.04 will include hot-swapping so it shouldnt be an issue soon =) en.wikipedia.org/wiki/Hot_swapping Apr 16, 2014 at 21:21
  • @KonnerRasmussen that was my initial thought. But when I press the display toggle button on my laptop's keyboard, a window pops up showing only the laptop screen. I see this when I plug the monitor back in, as it takes a few seconds for the list to update to include the external monitor.
    – Ryan
    Apr 16, 2014 at 21:24
  • I dont think the keyboard switch would actually do anything except turn the display off... refreshing the connections would be an entirely different beast... pressing that button may very well kill the display on the hardware level. if thats the case, the software may not know you even did anything to the display because the action may be done by the bios without any actual signal being sent downstream to the software... again you would need to refresh the devices for the software to realize any change has been made Apr 16, 2014 at 21:29

2 Answers 2

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I wondered about that one, too. Usually I do the following at the console:

xhost +
xrandr --auto
xhost -

Good news: In a few days, Xubuntu 14.04 will release, supporting monitor hot-plugging: details

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  • Looks like I know what I'll be doing tomorrow morning: updating to 14.04 and hoping against hope that hot-plugging monitors fixes this.
    – Ryan
    Apr 16, 2014 at 21:18
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    Boom! Updating to 14.04 seems to have fixed the problem. If I hot-unplug, I have to CTRL + ALT + F1 and then F7 to get back, but it works!
    – Ryan
    Apr 18, 2014 at 16:47
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I had a similar problem: after unplugging or disabling external monitor, the image flickered and I could not do anything.

I disabled texture compression in CompizConfig Settings Manager/OpenGL and it fixed my problem. Maybe it would fix yours too.

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    Welcome to AskUbuntu! This may help fix the problem. If you wish to improve your answer you can include screenshots, or be a little more specific in your answer.
    – No Time
    Aug 20, 2014 at 4:36

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