Dual Monitor: How to Get Full Resolution

Praveen Venkatachari vpraveen84 at gmail.com
Tue Apr 28 04:20:44 UTC 2009

This worked for me.
xrandr --output VGA --mode <your resolution>
xrandr --output VGA --mode 1680x1050

All you need to do is create a file ~/.xprofile with the above line.

Kent Borg wrote:
> Gleeful Report:
> This is for Ubuntu 8.04, Jaunty Jackalope.
> I have a notebook with an external VGA output jack.  When I plugged it
> into an external LCD that is 1440x900, it wouldn't give me full
> dimensions for that monitor.  Oddly, I have another install of 8.04 on a
> USB stick and it all works fine there.
> After some Googling and poking around, I fixed it!
> I think the key was that the dimensions mentioned in /etc/X11/xorg.conf
> were too small in both directions.  I boosted the vertical to 900 and
> the Display control panel was suddenly willing to mention the 1440x900
> choice, and when I chose that it offered to change the virtual
> resolution...and when I checked it had changed the horizontal.
> I logged off and on again, and it would let me go to 1440x900 on that
> other screen!
> Summary:
> If you have a multi-display setup and can't get full resolution on one
> of your displays, check /etc/X11/xorg.conf.  (It is a small file these
> days.)  Make sure the virtual display dimension is big enough for all
> your displays.
> Example:
> I have two displays 1024x768 and 1440x900.  I told the Display control
> panel (System->Preferences->Display) that the two displays are
> side-by-side.  This means I need a virtual display that is 2464 wide and
> 900 tall to fix them both in.
> In the file /etc/X11/xorg.conf I had this:
>   Section "Screen"
>       Identifier    "Default Screen"
>       Monitor        "Configured Monitor"
>       Device        "Configured Video Device"
>       SubSection "Display"
>           Virtual    2304 768
>       EndSubSection
>   EndSection
> Note the line that says "Virtual    2304 768".  Those dimensions are not
> big enough.  I now have "Virtual    2464 900" for that line, and I can
> have these two displays at full resolution.
> I don't know if this is a bug with the Display control panel, the
> installer, some part of the X11 system, or a combination, but this
> workaround worked for me.
> -kb, the Kent who wishes others similarly good luck.
> P.S.  I also messed around with "xrandr", it gave me key clues, but I
> don't think it would have been necessary to fix this.

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