Attaching a monitor via vga

Warren Block wblock at
Wed Jun 20 13:27:37 UTC 2012

On Tue, 19 Jun 2012, Chad Perrin wrote:

> On Tue, Jun 19, 2012 at 08:52:58PM -0400, David Tilbrook wrote:
>> I have a thinkpad t61p running freebsd9.0.  The window size is 1680x1050
>> -- a reasonable size -- but the screen itself is 38cm. (15") which is
>> irritatingly
>> small for my old eyes.
>> So I want to attach an external monitor via a vga cable, which I have been
>> doing with my RedHat thinkpad A31P for years.
>> I tried attaching Asus VE228H (1920x1080) but it would display
>> only part of the window (the top-left corner). I get a similar behaviour
>> with a Samsung SyncMaster.
>> When I tried to xinit with the monitor attached, it displays an even smaller
>> part of the screen. (On my previous thinkpad with a Samsung, to get a
>> reasonable full window I had to unplug the vga, start xinit, and then plug
>> in the vga, but I can live with that.)
>> My questions:
>> 1) What can I do to display the whole window on an external monitor?
>> 2) Is there a monitor out there that would better support such use?
>> 3) Would a Samsung T220HD 22" which claims to support 1680x1050
>>      work, and is there someone in Toronto who sells it and would let
>>      me test it? (Craigs list doesn't qualify).
> You probably want to look into using the xrandr command to configure
> output for connected monitors.  Try this first:
>    xrandr --auto
> If that does not work, you may have to do something more sophisticated.
> For instance, I have a shell script that looks like this for when I
> connect my laptop to an external monitor:
>    #!/bin/sh
>    xrandr --auto
>    xrandr --output LVDS1 --off
>    xrandr --newmode "1680x1050_60.00"  146.25  1680 1784 1960 2240  1050 1053 1059 1089 -hsync +vsync
>    xrandr --addmode VGA1 1680x1050_60.00
>    xrandr --output VGA1 --mode 1680x1050_60.00
>    xli -onroot -border black -center /path/to/enso_16x9.png

Adding a new mode should not be needed for most monitors.  I do this to 
set up the external video:

   xrandr --output VGA --above LVDS

That's to span a single desktop over both monitors.

Some desktop environments have their own ideas about which monitors are 
attached and what part of the desktop is shown, and that must be changed 
in the DE's settings.

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