How to get Screen Resolution 1440x900 in Ubuntu

Ubuntu 9.04 did not detect the native resolution of my new LCD monitor which was 1440x900.

Fix :

1. Get the Modeline - The first step is to get the modeline for the specific resolution and refresh rate using the gtf command. Here is a quick example:

$ gtf 1440 900 75

  # 1440x900 @ 75.00 Hz (GTF) hsync: 70.50 kHz; pclk: 136.49 MHz
  Modeline "1440x900_75.00"  136.49  1440 1536 1688 1936  900 901 904940  -HSync +Vsync

2. Configure xorg.conf - Next, add the Modeline to xorg.conf file located at /etc/X11/xorg.conf. You may want to take a backup of the file before editing it.

On a fresh Ubuntu installation the file may look small like this :

#Some comments on top
Section "Monitor"
 Identifier "Configured Monitor"
EndSection

Section "Screen"
 Identifier "Default Screen"
 Monitor  "Configured Monitor"
 Device  "Configured Video Device"
EndSection

Section "Device"
 Identifier "Configured Video Device"
EndSection

Section "ServerFlags"
 Option "DontZap" "True"
EndSection

Simply add the Modeline to the "Monitor" section, and set it as the preferred mode like this:

Section "Monitor"
 Identifier "Configured Monitor"
 Modeline "1440x900_75.00"  136.49  1440 1536 1688 1936  900 901 904 940  -HSync +Vsync
 Option          "PreferredMode" "1440x900_75.00"
EndSection

Section "Screen"
 Identifier "Default Screen"
 Monitor  "Configured Monitor"
 Device  "Configured Video Device"
EndSection

Section "Device"
 Identifier "Configured Video Device"
EndSection

Section "ServerFlags"
 Option "DontZap" "True"
EndSection

The option "PreferredMode" "1440x900_75.00" is used so that it becomes the default resolution on gnome, KDE desktops and GDM and KDM i.e. the login screen.

If this option is not used then there may be issues such that resolution after reboot or relogin reverts to a default like 1280x1200 as discussed here Bug.

Another fix could to be reconfigure X like: sudo dpkg-reconfigure xserver-xorg.