Hardware: Intel NUC6i3SYH, containing CPU i3-6100U with integrated graphics. BIOS version 0068 (latest). Previous OS: Ubuntu 16.04.5. Upgraded a few days ago to Ubuntu 18.04.1 LTS. This machine is used as headless server on a local network. It is controlled via another computer on the same network, using Remmina remote desktop client. Issue: since the Ubuntu upgrade is it no longer possible to view the NUC desktop remotely unless a display is physically connected to the NUC (either to HDMI or mini DisplayPort). Only when a display is connected is it possible to see the NUC's desktop on a remote computer using Remmina. Without it is only a black screen visible in Remmina. This issue was not present when using Ubuntu 16.04.1 ~ 16.04.5. Here it was not necessary to physically connect a display to the NUC in order to get remote desktop control. In Ubuntu settings have I switched off screen lock and switched off all power saving settings. This had no effect on this issue. My guess (but I'm no expert) is that the graphics processor switches itself off, or in a low-power mode, in case no display is detected. Which is nice for a mobile device (e.g. laptop), but not relevant for a NUC which is permanently powered. Is this a bug? Or is there a setting somewhere in Ubuntu 18.04 that I can fix this myself?
Jan - have you looked at guides/posts online regarding this, such as https://askubuntu.com/questions/1033436/how-to-use-ubuntu-18-04-on-vnc-without-display-attached ? I'm no expert on Ubuntu, but this sounds very much like it is a setup/configuration issue, and likely has nothing to do with the integrated graphics.
James Ausmus, thank you very much for pointing me in the right direction. I had been reading several items at AskUbuntu but didn't come across the one you linked to. That question has a reply by user Stefan Lemmens which worked for me. It basically involves three steps: (1) create a 20-intel.conf file, which creates a virtual display. (2) create a bash shell script to connect the Intel graphics to this virtual display. (3) have this shell script executed automatically upon startup/reboot of the machine. I have implemented this and it works on the NUC: even if no physical display is connected to the NUC does it believe to be connected to the virtual display and thus provides graphics output, which can be viewed remotely.
Glad that got you in the right direction!
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