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I have connected my laptop running Ubuntu 11.04 to an external monitor. Since then, I am not able to use my primary display.

Primary Display shows only a resolution of 640x480 at the moment. The external display is a 22" Monitor supporting a resolution of 1368x768.

Here is the part of xorg.conf 

    Section "ServerLayout"
    Identifier     "Layout0"
    Screen      0  "Screen0"
    InputDevice    "Keyboard0" "CoreKeyboard"
    InputDevice    "Mouse0" "CorePointer"
EndSection

Section "Files"
EndSection

Section "InputDevice"
    # generated from default
    Identifier     "Mouse0"
    Driver         "mouse"
    Option         "Protocol" "auto"
    Option         "Device" "/dev/psaux"
    Option         "Emulate3Buttons" "no"
    Option         "ZAxisMapping" "4 5"
EndSection

Section "InputDevice"
    # generated from default
    Identifier     "Keyboard0"
    Driver         "kbd"
EndSection


Section "Device"
        Identifier      "Intel 945G "
        Driver          "intel"
        Option "monitor-LVDS" "monLVDS"
        Option "monitor-VGA" "monVGA"
EndSection

Section "Monitor"
    Identifier     "Monitor0"
    VendorName     "Unknown"
    ModelName      "Unknown"
    HorizSync       28.0 - 33.0
    VertRefresh     43.0 - 72.0
    Option         "DPMS"
EndSection


Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection



Section "Screen"
        Identifier      "Default Screen"
        Device          "Intel Corporation 945G Integrated Graphics Controller"
        Monitor         "monLVDS"
        DefaultDepth    24
        SubSection "Display"
          Depth 24
          Modes "1440x900"
          Virtual 3040 1200
        EndSubSection
EndSection

Any idea how to get both the monitors running at full resolution ?

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  • Could you please provide your xorg.conf as text instead of as an image?
    – N.N.
    Sep 19, 2011 at 20:00
  • Sure, I am attaching the xorg.conf file
    – www.sapnaedu.in
    Sep 22, 2011 at 16:51

2 Answers 2

Reset to default
2
+100

First up, I'd try removing your xorg.conf file - recent versions of Xorg can generally work out most of your system's configuration automatically. Move it to somewhere safe, so you can restore it if necessary:

sudo mv /etc/X11/xorg.conf $HOME/xorg.conf.bak

then, restart your machine for the changes to take effect.

If you still see the broken behaviour, you can see what outputs X has found by using the xrandr utility. It will tell you the monitors it has found, and what resolutions they support. For example, this is what my machine says (some lines removed for brevity):

Screen 0: minimum 320 x 200, current 3360 x 1200, maximum 8192 x 8192
LVDS1 connected 1440x900+0+300 (normal left inverted right x axis y axis) 287mm x 180mm
   1440x900       60.0*+   59.9     50.0  
   1360x768       59.8     60.0  
   1152x864       60.0  
   1024x768       60.0  
   800x600        60.3     56.2  
   640x480        59.9  
VGA1 disconnected (normal left inverted right x axis y axis)
HDMI1 connected 1920x1200+1440+0 (normal left inverted right x axis y axis) 518mm x 324mm
   1920x1200      60.0*+
   1920x1080      50.0     60.0  
   1280x800       59.8  
   1024x768       60.0  
   800x600        60.3     56.2   
   640x480        60.0  
DP1 disconnected (normal left inverted right x axis y axis)
DP2 disconnected (normal left inverted right x axis y axis)

Next, manually configure your monitor setup with xrandr. Something like this would work (you may have to change VGA1 and LVDS1 to the actual names you see in the xrandr output earlier):

xrandr --output LVDS1 --auto --primary --output VGA1 --auto --right-of LVDS1

If that works, then you know that the low-level stuff is okay. Then, you can try to recreate this monitor configuration using the standard display properties UI.

If not, let us know what happens and we can suggest further ideas.

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  • +1 for suggesting trying without a hardcoded xorg.conf - the autoconfig should work.
    – ImaginaryRobots
    Oct 17, 2011 at 17:50
  • Thank you so much for your suggestion. It worked. However, I am facing another issue now, when I open any window, it just goes black.. may I will post with more details.. but your suggestion worked just fine..
    – www.sapnaedu.in
    Oct 19, 2011 at 18:10
0

Kubuntu 18.04

I had a similar problem recently. I removed an external display from a laptop and changed it to another USB-C port (4K resolution). KDE did not pick up the monitor so I tried rebooting. When I rebooted my primary display resolution was something like 500x400.

First I removed the ~/.local/share/kscreen file and rebooted. My secondary display then worked at full 4K resolution. I then removed the /etc/X11/xorg.conf file and rebooted.

Then ran xrandr to change the primary screen resolution back to what it was.

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