I'm new in this forum and even a beginner with ubuntu.

I've already tried to set the resolution of my monitor to 1440x900 but I can't get on because xrandr shows me error messages like:

xrandr: Failed to get size of gamma for output default
xrandr: Configure crtc 0 failed

Here there is the output of xrandr

Screen 0: minimum 640 x 480, current 1280 x 1024, maximum 1440 x 1024
default connected 1280x1024+0+0 0mm x 0mm
   1280x1024       0.0* 
   1024x768        0.0  
   800x600         0.0  
   640x480         0.0

As I said before, I would like to set resolution to 1440x900. Can anyone please help me to resolve this situation?

  • are you using sudo?
    – TellMeWhy
    Dec 6, 2015 at 18:29
  • @DevRobot I've tried even with sudo without success
    – beginner
    Dec 8, 2015 at 11:20
  • what video card are you using? What output do you get if you enter either of these two commands: lspci | grep VGA or sudo lshw -C video? Please edit your question and paste the output Dec 30, 2015 at 17:04

1 Answer 1


Create a xorg.conf file in \etc\X11 with the the following contents:

Section "Screen"
    Identifier   "Screen0"
    Device       "Device0"
    Monitor      "Montior0"
    DefaultDepth 24
    Subsection   "Display"
        Depth      24
        Modes      "1024 x 768" "1440 x 900"

Section "Monitor"
    Identifier  "Monitor01"
    VendorName  "Monitor0"
    ModelName   "Model0"
    HorizSync   30 - 300
    VertRefresh 30 - 500
    Modeline    "1440x900_60.00"  129.00  1440 1528 1680 1920  1080 1083 1087 1120 -hsync +vsync

Change the Modeline part so that it contains the output of your cvt 1440 900 command.
Reboot and try your xrandr commands again.
If you boot into a TUI, you can remove the xorg.conf file with:

sudo rm /etc/X11/xorg.conf

NOTE: The ideal situation would be to google the name of your monitor, get the horizontal sync and vertical refresh rates and replace the default values above.

  • I created a new xorg.conf file in \etc\X11 without success, not even by changing the default "HorizSync" and "VertRefresh" values with those specific for my monitor. So even now i can't select 1440x900 as the resolution (noteven by xrandr)
    – beginner
    Dec 8, 2015 at 11:18

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