Widescreen LCDs and Ubuntu Linux

Ubuntu (with it’s default gnome install) and X don’t really support widescreen LCDs out of the box. This is somewhat unfortunate, as I have a new widescreen with an extra VGA input that is just begging to be used for something while I use the DVI for the Mac.

The essential problem is that the Xorg configuration files don’t have modelines for the 1680x1050x60hz resolution that I need, and I can’t find a way to specify arbitrary resolutions in the Gnome Screen Resolutions configuration applet. (And the help is no help, it helpfully tells you how to change resolutions, but not what to do if the resolution is not listed.)


The first step is to get the configuration file to recognize the monitor. This is probably going to need to be done from a text console or ssh login.

sudo dpkg-reconfigure xserver-xorg

Do what you can there, I wasn’t able to get it to do anything other than recognize the monitor type. So, into the config file. The file of interest is /etc/X11/xorg.conf, we will be adding a modeline to it and removing some of the alternate resolutions in the 24 bit color section.

Add the modeline line shown here:

Section "Monitor"
        Identifier      "DELL 2005FPW"
        Option          "DPMS"
        HorizSync       30-83
        VertRefresh     60
        Modeline "1680x1050@60" 154.20 1680 1712 2296 2328 1050 1071 1081 1103

and change the preferred display resolutions in the screen section:

Section "Screen"
        Identifier      "Default Screen"
        Device          "ATI Technologies, Inc. Radeon 7000 VE (RV100 QY)"
        Monitor         "DELL 2005FPW"
        DefaultDepth    24
        SubSection "Display"
                Depth           1
                Modes           "1680x1050"
        SubSection "Display"
                Depth           24
                Modes           "1680x1050"

I removed all the 4:3 resolutions, and the smaller ones just for good luck.

Starting X, all looked good until Gnome took control again and pushed me into a lower res widescreen mode, but this time the correct native resolution was available in the Screen Resolution applet. Selected, applied, and once the monitor automatically recalibrated, everything was as it should be.

There are a few modline calculators found on google, I used this one with my the 1680x1050x60hz parameters to generate a modeline to add to the xorg config file. If you’re attempting to do this to a laptop, you’ll probably need that link.

I’m not going to belabor the point that it’s 2005 and this is one of the friendlier linux distros that I’ve dealt with.

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