Multi-monitor setup

If configured to use Xinerama libraries in config.mk, dwm can automatically detect configured screen outputs (monitor, overhead projector, etc.) and their resolutions and draw the windows in the output area accordingly.

Configuring monitors

One of the easiest ways to configure screen outputs is via the RandR X server extension using the xrandr tool. Without arguments it will list the current configuration of screen outputs.

xrandr

For each connected output the supported resolution modes will be printed.

Mirroring two outputs

dwm will assume that two outputs should display identical windows and tags if:

one of them is configured to display in the same area as the other (--same-as switch)
they have the same resolution

After connecting a monitor, this could be an example of a mirroring setup

xrandr --output VGA1 --auto --same-as LVDS1 --mode 1024x768
xrandr --output LVDS1 --mode 1024x768

The --auto switch enables the output after it was connected.

Two independent outputs

If two screen outputs have different resolutions, dwm assumes that they should display different windows and tag sets. It may therefore be necessary to instruct the X server via the xrandr tool to draw the outputs in different areas of the screen, as it may default to --same-as and the areas would overlap.

After connecting a monitor, this could be an example of such a setup

xrandr --output VGA1 --auto --right-of LVDS1

In this case the --auto switch enables the output after connecting and also sets its preferred resolution mode.