Re: Using a second monitor

[saint@eng.it]

Robert D. Hilliard writes:
 > Reply To:  bobhilliard@gmail.com

> I have a new Dell Ispiron that dual boots Windows 7 and Debian 7.4.
 > The new machine uses the F1 key to connect to the second monitor, but
 > it only works in Windows - In Debian pressing F! is a noop.

I would advice to use xrandr.

First issue the

xrandr -q command

in a terminal so that you can see which monitors are available.

Here is what the output on my laptop:

08:42:12 [24] $xrandr -q
Screen 0: minimum 320 x 200, current 2390 x 768, maximum 8192 x 8192
LVDS1 connected 1366x768+1024+0 (normal left inverted right x axis y axis) 344mm x 194mm
   1366x768       60.0*+
   1360x768       59.8     60.0  
   1024x768       60.0  
   800x600        60.3     56.2  
   640x480        59.9  
VGA1 connected 1024x768+0+0 (normal left inverted right x axis y axis) 304mm x 228mm
   1024x768       75.1     75.0     70.1     60.0* 
   800x600        72.2     75.0     60.3  
   640x480        72.8     75.0     60.0  
   720x400        70.1  
HDMI1 disconnected (normal left inverted right x axis y axis)
DP1 disconnected (normal left inverted right x axis y axis)

VGA1 on a laptop SHOULD be always be the VGA connector, on my machine
the screen of the laptop is LVDS1 and it is the default primary
monitor. IF I understood the manual page, the primary monitor is also
the first one listed with the -q option.

Please note that there are 2 other connectors that are not in use
HDMI1 and DP1.

Once you know the monitor names you can build the command that better
suits your needs. In the following example I will assume that the
external monitor is named VGA1 and the laptop monitor is named LVDS1.

If you just need to have the external monitor as only output (you do
not use the laptop monitor)

xrandr --output VGA1 --primary

that turns the external monitor into the primary (this comes from one
of the pages mentioned in this thread). I will use this command with a
slight change:

xrandr --output VGA1 --primary --output LVDS1 --off

that shuts down the laptop monitor and saves some power. To turn the
monitor on you must issue the

xrandr --output LVDS1 --mode widthxheight.

This command

xrandr -output VGA1 -same-as LVDS1

turns the external monitor into a mirror of the internal monitor
without changing the primary monitor.

Reading the xrandr manual you will discover what options suits your
problem best.

One last thing. Since you do not want to issue this command over and
over again, you can place it into the .xsession file (if you use
xdm/gdm/kdm) or .xinitrc file if you log on in a text console and then
manually run the startx program.

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