DisplayLink

Kernel

You need to activate the following kernel options:

Device Drivers --->
    Graphics support --->
        <*> DisplayLink
        <*> Frame buffer Devices --->
            <*> Displaylink USB Framebuffer support

After booting into the new kernel the external monitor should show a green background image. That means the kernel module is loaded and the device works, it also creates the device in /dev/fb0.

X driver

For X11 drivers, you can use x11-drivers/xf86-video-fbdev or x11-drivers/xf86-video-displaylink from the x11 overlay.

• xf86-video-fbdev

Portage uses the USE_EXPAND variable called VIDEO_CARDS to enable support for various graphics cards in packages. Setting VIDEO_CARDS to appropriate value(s) will pull in the correct driver(s):

<syntaxhighlight lang="bash">VIDEO_CARDS="fbdev"</syntaxhighlight>

Substitute the name of the driver(s) to be used. Common choices include nouveau, nvidia, radeon, and intel. After setting or altering VIDEO_CARDS values remember to update the system using the following command so the changes take effect:

• xf86-video-displaylink

Software

For this method, we need another input device driver called x11-drivers/xf86-input-void:

<syntaxhighlight lang="bash">INPUT_DEVICES="... void ..."</syntaxhighlight>

Also install x11-misc/x2x:

xorg.conf.DL

We configure two independent xorg.confs for each device and initialize the desktop using ~/.xinitrc scripts.

Create the file /etc/X11/xorg.conf.DL:

<syntaxhighlight lang="xorg.conf">Section "Device"
    Identifier "DisplayLinkDevice"
    driver "displaylink"         # Or fbdev depending on what you installed
    Option "fbdev" "/dev/fb0"    # You have to use the correct framebuffer device here
EndSection

Section "Monitor"
    Identifier "DisplayLinkMonitor"
EndSection

Section "Screen"
    Identifier "Default Screen"
    Device "DisplayLinkDevice"
    Monitor "DisplayLinkMonitor"
    SubSection "Display"
        Depth 16         # 24bit works fine but for USB 2.0 a lot of data
        Modes "1280x1024"
    EndSubSection
EndSection

Section "ServerLayout"
    Identifier "Server Layout"
    Screen 0 "Default Screen" 0 0
    Option "AllowMouseOpenFail" "True"
    InputDevice "Keyboard0" "CoreKeyboard"
    InputDevice "Mouse0" "CorePointer"
EndSection

Section "ServerFlags"
    Option "AllowEmptyInput" "false"
    Option "AutoAddDevices" "false"
    Option "AutoEnableDevices" "false"
EndSection

Section "InputDevice"
    Identifier "Keyboard0"
    Driver "void"
EndSection

Section "InputDevice"
    Identifier "Mouse0"
    Driver "void"
EndSection</syntaxhighlight>

.xinitrc2

Next we create the ~/.xinitrc2 for your external display. Create and customize the file to your needs, here is an example:

<syntaxhighlight lang="bash"># DPMS stuff
## turn on monitor
xset dpms force on
## disable sleep modes etc.
xset -dpms
## disable screensaver
xset s off

# turn off beep
xset -b

# activate zapping (ctrl+alt+Bksp killall X)
setxkbmap -option terminate:ctrl_alt_bksp

# Set the background using feh
feh --bg-scale /usr/share/slim/themes/capernoited/background.jpg

# compositoring
xcompmgr -c -t-5 -l-5 -r4.2 -o.55 &

# start programs
wicd-client &
mrxvt &
# start the actual window manager
exec /usr/bin/awesome</syntaxhighlight>

displaylink.sh

This is the actual script that starts the second instance of X server. Make it executable and save it somewhere in your home folder, in this example we save it to ~/.displaylink.sh:

<syntaxhighlight lang="bash">#!/bin/sh
xinit ~/.xinitrc2 -- /usr/bin/X :1 -xf86config xorg.conf.DL -novtswitch -sharevts -audit 0 -layout "Screen Layout" vt12 &
sleep 5
x2x -west -from :0 -to :1 &</syntaxhighlight>