External HDMI display detected, but not working

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?

5 Answers

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:

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

I had the same problem. Only one monitor at the time was working. This partially solved my issue.

I tried to change the resolution of the monitor with the highest resolution to something smaller. This already made both of the monitors to work.

Then, I increased the resolution of the monitor. Unfortunately, I am still not able to make the bigger monitor work at full resolution (2560x1440) but only at 1920 x 1200. Indeed, when I switch to full resolution (2560x1440) the other monitor disappears.

I have the same problem...

Monitor says "no signal" but xrandr says it is connected...

If I tell xrandr make any sort of change (it must be a change) then the display is reset and it all comes back.

For example, have xrandr turn it off and on...

xrandr --output DP-1-1 --off
xrandr --output DP-1-1 --auto

However it losses its position information and just becomes a clone, until I again reset the position. Any windows on that display get moved to make them at least partially visible in the other display, though I have found it shift a LOT of windows which should not have been effected too. Basically it is a horrible fix.

This fixes the problem some of the time...

xset dpms force suspend # or standby or off (same result)
xset dpms force on

This is the best solution I found so far, but depends on your setup...

Move the display just a little (one pixel), then moving it back! It is enough of a change to get xrandr to resurect the monitor and does not cause my application windows to suddenly change position.

xrandr --output DP-1-2 --pos 1921x0; # shift one pixel
xrandr --output DP-1-2 --pos 1920x0; # shift it back

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.

Unfortunately I have the same problem here, after instsalling the newest nvidia driver on my Omen15 laptop. By the way I only managed to install the driver sucsessfully when I disabled my secure boot.

My situation is exactly the same as yours, second monitor detected but not showing anything.

I have tried the following methods that I could find:

• Changing the second/main monitor's resolution (using CLI and GUI)
• Install vbetool via:

sudo apt-get install vbetool

• To install all recommended drivers via:

sudo ubuntu-drivers autoinstall

And I did not try the following:

• re-installing nvidia driver (it will make me even frustrated)

However, none of them worked for me.

A few days later, when I again swicthed back to my Ubuntu after working with my Win10, the second monitor works! Just like how it works under Windows!

I have no idea of this, but folks, hope this give you some light after the frastruation...

Cheers!