Jtdcftul

I am using Dell XPS 13 9360 with Ubuntu 16.04. It does not have a HDMI slot, so I have a USB-C-to-HDMI adapter, which is then connected to my monitor: DELL S2240L.

In System Settings > Displays, I can see that the monitor is detected properly and is turned on. If I try to move my mouse cursor out of my laptop screen and into the external display area, I can see the cursor leaving my laptop screen. If I keep moving my cursor further away and try to move back, it takes some time to reappear onto my laptop screen, so there is even the display 'space' for the cursor to move to.

However, the monitor keeps saying "no signal" and therefore goes to power-saving mode. I am pretty sure that the adapter doesn't have a problem because the computer is detecting the monitor. The monitor also works fine when connected to a different (Windows) desktop.

Here is the result for running sudo lshw -C video :

*-display               

   description: VGA compatible controller

   product: Intel Corporation

   vendor: Intel Corporation

   physical id: 2

   bus info: pci@0000:00:02.0

   version: 02

   width: 64 bits

   clock: 33MHz

   capabilities: pciexpress msi pm vga_controller bus_master cap_list rom

   configuration: driver=i915 latency=0

   resources: irq:286 memory:db000000-dbffffff memory:90000000-9fffffff ioport:f000(size=64) memory:c0000-dffff

and xrandr :

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) 294mm x 165mm

   1920x1080     59.93*+

   1680x1050     59.95    59.88  

   1600x1024     60.17  

   1400x1050     59.98  

   1280x1024     60.02  

   1440x900      59.89  

   1280x960      60.00  

   1360x768      59.80    59.96  

   1152x864      60.00  

   1024x768      60.04    60.00  

   960x720       60.00  

   928x696       60.05  

   896x672       60.01  

   960x600       60.00  

   960x540       59.99  

   800x600       60.00    60.32    56.25  

   840x525       60.01    59.88  

   800x512       60.17  

   700x525       59.98  

   640x512       60.02  

   720x450       59.89  

   640x480       60.00    59.94  

   680x384       59.80    59.96  

   576x432       60.06  

   512x384       60.00  

   400x300       60.32    56.34  

   320x240       60.05  

DP-1 connected 1920x1080+1920+0 (normal left inverted right x axis y axis) 476mm x 267mm

   1920x1080i    60.00*   50.00    59.94  

   1280x1024     75.02    60.02  

   1152x864      75.00  

   1280x720      60.00    50.00    59.94  

   1024x768      75.03    60.00  

   800x600       75.00    60.32  

   720x576       50.00  

   720x480       60.00    59.94  

   640x480       75.00    60.00    59.94  

   720x400       70.08  

DP-2 disconnected (normal left inverted right x axis y axis)

Any suggestions/insights?

I had the same issue with a Dell XPS 13 9360 running Ubuntu 16.04 using a USB-C da200 adapter. Try setting the resolution of the second screen to something low, say 1440x900 or lower. If that makes the second screen work (as it did for me) then you're running into a bug with the adapter, detailed here:

https://bugs.freedesktop.org/show_bug.cgi?id=93578

Updating kernels solved the issue for me. I was on kernel 4.10.xx, upgrading to kernel 4.12.14 worked for me.

Try this and see if it works:

xrandr --output eDP-1 --mode 1920x1080 --output DP-1 --mode 1920x1080 --same-as eDP-1

and see if it works. That should create a mirror but that's exactly what we want to test first, we want to test whether mirroring works. Then we can move forward.

I've (literally) never had any luck in setting up my monitor setup the way I want from any graphical utility so I resorted to the command line via xrandr and I got it to work perfectly in my case.

I have the same issue. Overnight, my left monitor doesn't display. It seems to be connected but no signal getting through.

I'm using lightdm as display manager now and have just upgraded to 18.10 from 18.04 hoping that would help. Still the same issue. I have tried the changing resolution but it either makes no difference of it says not found:

$ xrandr --output DP-2 --mode 1920x1080 --output DP-1 --mode 1920x1080 --same-as DP-2
xrandr: cannot find mode 1920x1080

Any ideas anyone?

xrandr output:
Screen 0: minimum 320 x 200, current 2944 x 1080, maximum 8192 x 8192
DP-1 connected 1024x768+0+0 (normal left inverted right x axis y axis) 531mm x 299mm
1024x768 60.00*
800x600 75.00 60.32

720x576 50.00 50.00 50.00

720x480 60.00 60.00 59.94 59.94 59.94

640x480 75.00 72.81 66.67 60.00 59.94 59.94

720x400 70.08

HDMI-1 disconnected (normal left inverted right x axis y axis)
DP-2 connected primary 1920x1080+1024+0 (normal left inverted right x axis y axis) 531mm x 299mm
1920x1080 60.00*+ 60.00 50.00 59.94

1920x1080i 60.00 50.00 59.94

1680x1050 59.95

1280x1024 75.02 60.02

1440x900 74.98 59.89

1280x720 60.00 60.00 50.00 50.00 59.94

1024x768 75.03 60.00

800x600 75.00 60.32

720x576 50.00 50.00 50.00

720x480 60.00 60.00 59.94 59.94 59.94

640x480 75.00 72.81 66.67 60.00 59.94 59.94

720x400 70.08

HDMI-2 disconnected (normal left inverted right x axis y axis)
DP-3 disconnected (normal left inverted right x axis y axis)
HDMI-3 disconnected (normal left inverted right x axis y axis)