02-apr-2017: Dokuwiki and its plugins were upgraded to the latest release.
28-mar-2016: Welcome to our new server! Faster and less prone to crashing.

Welcome to the Slackware Documentation Project

Dual Monitors

Known to work on Slackware 14.1 and XFCE

If you are running XFCE and your secondary monitor isn't working, check and make sure it's enabled in XFCE's SETTINGS:

SETTINGS > SETTING MANAGER > DISPLAY > display name in column on left > USE THIS OUTPUT

Mirror Monitors

By default, XFCE (the WM I use) seems to do this by default.

Extend Desktop To Second Monitor

To extend the desktop to a second monitor (as opposed to mirror the desktop), you need to use xrandr to move the desk top over X number of pixels. Where X = your LEFT monitor's X resolution.

1) Make sure your video card's output is being 'seen' by the system and get the output names:

 xrandr -q 

( Make note of the name of your secondary monitor. )

2) Move the secondary monitor over to the right

 xrandr --output HDMI-0 --pos 1024x0 # to move the VGA screen 1024 pixels to the right. 

EXAMPLE: Here's my machine. DVI-I-2 is my LEFT monitor and HDMI-0 is my RIGHT monitor.

[arfon@darkstar ~]$ xrandr -q
Screen 0: minimum 8 x 8, current 1920 x 1080, maximum 16384 x 16384
DVI-I-0 disconnected (normal left inverted right x axis y axis)
DVI-I-1 disconnected (normal left inverted right x axis y axis)
DVI-I-2 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 598mm x 336mm
   1920x1080      60.0*+
   1680x1050      60.0  
   1440x900       59.9  
   1280x1024      75.0     60.0  
   1280x960       60.0  
   1280x800       59.8  
   1280x720       60.0  
   1152x864       75.0  
   1024x768       75.0     70.1     60.0  
   800x600        75.0     72.2     60.3     56.2  
   640x480        75.0     72.8     59.9  
HDMI-0 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 521mm x 293mm
   1920x1080      60.0*+   59.9     60.1     60.0  
   1440x480       60.1  
   1280x720       60.0     59.9  
   1024x768       75.0     70.1     60.0  
   800x600        75.0     60.3  
   720x480        59.9     60.1  
   640x480        75.0     59.9     59.9  
DVI-I-3 disconnected (normal left inverted right x axis y axis)
[arfon@darkstar ~]$ xrandr --output HDMI-0 --pos 1920x0

Cool Switching Scripts

Here's a script I wrote to toggle between extended dual monitors and a single monitor-

#!/bin/bash
vPRIMARYMONITOR="DVI-I-0" # <--- CHANGE THIS.  Find using "xrandr -q"
vLOC="--right" # <--- Change this if you want the second monitor in another position. CHOICES: --above  --below  --left  --right
vEXT=$(xrandr -q | grep " connected" | grep -v $vPRIMARYMONITOR | awk '{print $1}' | head -n 1 )
vOnOff=$(xrandr -q | grep $vEXT | sed 's/primary//g' | awk '{print $3}'| sed 's/[0-9]*x[0-9]*+[0-9]*+[0-9]*/ON/g' )
[ "$vOnOff" != "ON" ] && vOnOff="OFF"
if [ "$vOnOff" = "OFF" ]; then
        /usr/bin/xrandr --output $vEXT --auto $vLOC $vPRIMARYMONITOR
        else
        /usr/bin/xrandr --output $vEXT --off
        fi

Script to toggle a mirrored monitor-

#!/bin/bash
vPRIMARYMONITOR="DVI-I-0" # <--- CHANGE THIS.  Find using "xrandr -q"
vEXT=$(xrandr -q | grep " connected" | grep -v $vPRIMARYMONITOR | awk '{print $1}' | head -n 1 )
vOnOff=$(xrandr -q | grep $vEXT | sed 's/primary//g' | awk '{print $3}'| sed 's/[0-9]*x[0-9]*+[0-9]*+[0-9]*/ON/g' )
[ "$vOnOff" != "ON" ] && vOnOff="OFF"
if [ "$vOnOff" = "OFF" ]; then
	/usr/bin/xrandr --output $vEXT --auto
	else
	/usr/bin/xrandr --output $vEXT --off
	fi

Sources


In Other Languages
Translations of this page?:
QR Code
QR Code howtos:window_managers:dual_monitors (generated for current page)