Manjaro XFCE: video outputs (Multi-monitor)

[josmo]

Connected USB type C to DP device: it works in mirror mode.

Manjaro XFCE only displays one video output: "default"

Code:

$ xrandr -q
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 1920 x 1080, current 1920 x 1080, maximum 1920 x 1080
default connected 1920x1080+0+0 0mm x 0mm
  1920x1080      0.00*

GUI settings ($ xfce4-display-settings -m): only one monitor ("default")

How to configure two separate monitors?

P.S. Default Debian: no problems (eDP-1 and DP-1 video outputs).


that came up a few times on manjaro arm forums
the suggestion was swap drivers :

sudo pacman -S mesa-git
sudo pacman -R xf86-video-fbturbo # or xf86-video-fbturbo-git
then reboot

it worked for me