GDBus.Error when trying to enable second screen

Solution 1:

dconf write /org/gnome/settings-daemon/plugins/xrandr/active true did nothing and arandr looks pretty incomprehensible to me. If you are otherwise stymied, it is worth giving xrandr a try. The documentation is here: http://www.thinkwiki.org/wiki/Xorg_RandR_1.2#First_discover_what_we_have

And I was able to fix this by doing:

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

Let me explain these:

The first command is to see what displays I have connected.

$ xrandr --current
Screen 0: minimum 320 x 200, current 3200 x 1080, maximum 8192 x 8192
LVDS1 connected 1280x800+0+0 (normal left inverted right x axis y axis) 261mm x 163mm
1280x800       60.0*+
1024x768       60.0
800x600        60.3     56.2  
640x480        59.9  
VGA1 connected 1920x1080+1280+0 (normal left inverted right x axis y axis) 509mm x 286mm
1920x1080      60.0*+
1280x1024      60.0  
1440x900       59.9  
1280x800       59.8  
1152x864       75.0  
1024x768       70.1     60.0  
800x600        60.3     56.2  
640x480        66.7     60.0  
720x400        70.1  
HDMI1 disconnected (normal left inverted right x axis y axis)
DP1 disconnected (normal left inverted right x axis y axis)

There is much extraneous data, but I only need the names of the two displays. I see:

LVDS1 connected

and

VGA1 connected

And I think it is safe to assume that VGA is the external monitor. So then I turn it off

xrandr --output VGA1 --off

and back on again

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

and when I move my cursor to the right edge of the laptop screen, it appears on the external monitor. Success.

Solution 2:

Calling:

dconf write /org/gnome/settings-daemon/plugins/xrandr/active true

solved the problem for me.

Depending on your graphics card, its specific configuration tool can do the dual screen configuration too e.g. nvidia-settings, ... an

Solution 3:

I came here having issues on display settings after installing Cinnamon in Xubuntu. Doing so gave me two "displays" dialogs, the ubuntu one giving me the gdbus error. Open the other one (Cinnamon) to get it right.

https://github.com/linuxmint/Cinnamon/issues/2506#issuecomment-26671162 - thanks