Virtual screen

Ever wondered if you could drag a window from your PC to a phone or tablet standing on your desk? It turns out you can!

I wrote this guide, because I've only found bits and pieces around, with many things being outdated or not working.

How to

1) Create a virtual screen

Install evdi kernel module

git clone
cd evdi/module

make && sudo make install
# or
sudo make install_dkms

Add evdi to /etc/modules-load.d/local.conf.

Add options evdi initial_device_count=1 to /etc/modprobe.d/local.conf.

WARNING! This next step will freeze your Xorg, so you might want to reboot instead or be clever about killing your Xorg or something.

sudo modprobe evdi

2) Set a resolution and position to your virtual screen


set -- $(cvt "$w" "$h" 60 | grep Modeline)
shift 2

xrandr --newmode "$name" "$@"
xrandr --addmode DVI-I-1-1 "$name"
xrandr \
    --output DVI-I-1-1 \
    --mode "$name" \
    --left-of eDP-1

3) Share your virtual screen with VNC

geometry="$(xrandr | grep DVI-I-1-1 | cut -d" " -f 3)"
x0vncserver \
    -display :0 \
    -SecurityTypes none \
    -Geometry "$geometry"
# or
x11vnc \
    -display :0 \
    -clip "$geometry" \

For x0vncserver instead of -SecurityTypes none you might want to use -PasswordFile option instead. Consult your man page.

4) (optional) Attach Android device through USB cable

adb reverse tcp:5900 tcp:5900

Now you can point your VNC client application (like MultiVNC) to localhost:5900.

What is wrong in other guides

Using obsolete intel driver

Intel driver has Option "VirtualHeads", but you really want to stick to default modesetting driver.

Using dummy driver

According to ArchLinux wiki page "Extreme_Multihead#VNC"

It is in principle possible to set up a dummy device alongside a real device by adding a dummy device and xinerama configuration to xorg. It is tricky to have this configuration working properly, and it is not ideal for laptops, as you won't be able to hotplug monitors.

Using xrandr --fb to enlarge screen size

You can't make a window go fullscreen or snap to the edges.

Using an unused output

It fails for me. I have a DP-1 in xrandr, but no physical DisplayPort output.

$ xrandr --output DP-1 \
    --mode 1280x720_60.00 \
    --left-of eDP-1
xrandr: Configure crtc 2 failed