On Sun, 29 Oct 2017 at 13:37:00 +0200
Lars Noodén <lars.nooden@???> wrote:

> On 10/29/2017 01:01 PM, Alessandro Selli wrote:
> [snip]> Check the output of xrandr --query for pointers.
>
> Thanks. I can see that eDP-1 and HDMI-1 are both connected.
>
> $ xrandr --query | grep -E '^[[:alpha:]]'
> Screen 0: minimum 320 x 200, current 3840 x 1080, maximum 8192 x 8192
> eDP-1 connected primary 1920x1080+0+0 (normal left inverted right x axis
> y axis) 290mm x 170mm
> DP-1 disconnected (normal left inverted right x axis y axis)
> HDMI-1 connected 1920x1080+1920+0 (normal left inverted right x axis y
> axis) 531mm x 299mm
> HDMI-2 disconnected (normal left inverted right x axis y axis)
> DP-2 disconnected (normal left inverted right x axis y axis)
> HDMI-3 disconnected (normal left inverted right x axis y axis)
> DP-3 disconnected (normal left inverted right x axis y axis)

$ xrandr --output eDP-1  --auto \
         --output HDMI-1 --auto \
         --same-as eDP-1

You want HDMI-1 to be --same-as eDP-1, however I see HDMI-1 is set at
1920x1080+1920+0 and eDP-1 at 1920x1080+0+0, that is HDMI-1 is set --right-of
eDP-1. Try other placement options, if nothing works try setting HDMI-1
--off and then back --auto or --mode 1920x1080 --same-as eDP-1.


Just yesterday I had a like issue on an HDMI external projector at a
conference in a local University; I tried all sort of settings until it
worked, but I do not remember what was that finally worked and why other
settings did not. :-/