I found a page that might be just the thing for you.....
https://wiki.ubuntu.com/X/Config/Resolution
Relevant section:
Adding undetected resolutions
Due to buggy hardware or drivers, your monitor's correct resolutions may not always be detected. For example, the EDID data block queried from your monitor may be incorrect.
If the mode already exists, but just isn't associated for the particular output, you can add it like this:
xrandr --addmode S-video 800x600
If the mode doesn't yet exist, you'll need to create it first by specifying a modeline:
xrandr --newmode <Mode``Line>
You may create a modeline using the gtf or cvt utility. For example, if you want to add a mode with resolution 800x600 at 60 Hz, you can enter the following command: (The output is shown following.)
cvt 800 600 60
# 800x600 59.86 Hz (CVT 0.48M3) hsync: 37.35 kHz; pclk: 38.25 MHz
Modeline "800x600_60.00" 38.25 800 832 912 1024 600 603 607 624 -hsync +vsync
Then copy the information after the word "Modeline" into the xrandr command:
xrandr --newmode "800x600_60.00" 38.25 800 832 912 1024 600 603 607 624 -hsync +vsync
After the mode is entered, it needs to be added to the output using the --addmode command as explained above.
Best Answer
I'll show you an example of how you can set your monitor resolution.
Get the Modeline with the following command.
60is the monitor refresh rate in Hz. You have to know your monitor refresh rate!!!The output looks like this. Copy the modeline after
Modelineto use it in the next command.:Create a new mode with the copied modeline and xrandr.:
With the following command, you get the connected port.
The output looks like this. As you can see, in my case the connected port is
DVI-0.:Add the new mode using your connected port.:
Change the monitor resolution.: