external monitor resolution not recognized

I have an external monitor capable of a resolution of 1440x900, but when I connect it to my laptop (Dell XPS L502X) the maximum resolution I can get is 1024x768. I have a hybrid graphics card, but the monitor is connected to the mini-display port using a VGA adapter, which should be running of the integrated graphics card, not the Nvidia card. Anyone know how I can increase the external monitor resolution?

I fixed this problem so I thought I’d post the solution in case anyone else has this problem.

From terminal, run :

cvt 1440 900 60

Syntax is horizontal res, vertical res, refresh rate. Replace above with your own settings.

In my case, the output from the above is:

# 1440x900 59.89 Hz (CVT 1.30MA) hsync: 55.93 kHz; pclk: 106.50 MHz
Modeline "1440x900_60.00"  106.50  1440 1528 1672 1904  900 903 909 934 -hsync +vsync

Create a shell script with the following:

xrandr --newmode "1440x900_60.00"  106.50  1440 1528 1672 1904  900 903 909 934 -hsync +vsync
xrandr --addmode DP-1 1440x900_60.00

Replace everything after “–newmode” with your own settings from the output of “cvt” and replace DP-1 with whatever interface you need.

Place the script in ~/.config/autostart-scripts/ and make sure it’s executable.

The correct resolution is now automatically selected when I plug in the external monitor.

You can add the modeline to the appropriate /etc/X11/xorg.conf.d file for monitors also