Intel NUC HDMI external Monitor Issue

Im facing an issue when i turn on my Intel NUC appliance and no monitor is connected to it. The problem is when i connect a Monitor there is no HDMI signal. I manage to solve that issue on a raspberry pi 3B+ by adding RESIN_HOST_CONFIG_hdmi_force_hotplug=1 but thats works only for raspberries.
I’d appreciate any help, thank you.

Hi, can you let me know what image you are deploying? Also, is the HDMI monitor connected before you turn on the NUC?

Image: intel-nuc-node:10-build
App: variation of app
Monitor: Viotek.
If i connect the monitor before i turn on the appliance evering works fine, the issue comes when i connect the monitor after turn on the NUC

Thanks for sharing. Do you see the balena logo when the device boots? If you are running a development image you should also be able to see the boot log on the screen.

We are currently using a Porduction Image and no logo is showed on the screen when the monitor is connected.

Ok, production images should show the logo, so this is probably not related to the app you are deploying. Can you confirm that you have the HDMI connected before powering the device?

As i said early the issue is when i connect the display after i turn on the device, if i connect the monitor and turn on the device everithing works as expected.

Oh I did not get it. So I don’t think it’s possible for the NUC to detect the monitor if it has already booted. I’ll ask internally to see if anyone has any tricks for this.

This solve the issue on the RB Pi, you can ask for a similar approach for Intel NUC.

Hi, colleagues have suggested to look into Intel’s BIOS, i don’t have one but maybe you can check that?

I need you to be more specific.

You would need physical access to a device, reboot it and press F2 (for an intel NUC) to access BIOS settings.
The NUC’s BIOS has a lot of options, looking through it I only found very few not very promising options regarding the HDMI ports.
I will look if anyone in balena has a more firm idea of what options to modify.

By the way I am using a USB-C monitor on my intel NUC and I am pretty sure I can plug that in at any time I like.

Hi @samothx, thanks for your reply, for us is the same, if the HDMI cable is connected when the device powers up, we can plug/unplug any number of times and is going to work. When is not working is when the device powers up and nothing is connected in the HDMI port. Our question comes because we could fix it using RESIN_HOST_CONFIG_hdmi_force_hotplug =1 in a Raspberry Pi 3B+, but not for Intel NUC

I have just given this a try with my intel NUC running on Windows 10 and it seems that I can plug in my HDMI device at any time and receive output. This would suggest that it depends on the OS rather than being a BIOS issue, although it could still be caused by different hardware (NUC, Monitor, cables) or BIOS versions. I will talk to someone with a NUC device running on Balena to see if they have the same issues.

A colleague has been running the test on under balena 2.47.0+rev1 (development image) on an Intel NUC 7i7BNH and he does not see the problem. Can you please supply the type of NUC you are using and the version of Balena OS you are running ?

Hi @samothx we are using BalenaOS 2.47.0+rev1 and 2.46.0+rev1 and if by the type of NUC you refer to the type of hardware, we are using an Intel Celeron J3160 for CPU with 8GB of RAM (we do not use the specific Intel NUC from Intel, due to the OS working for generic x86 devices unless I’m wrong). Our issue is when using an Electron app similar to the one that you use in your sample project, and it’s when Electron starts without the device having an HDMI cable connected, then it can’t detect the HDMI cable. We could fix it in RPi, but not for Intel NUC device.

Hi. Sounds like you are running the Intel NUC image on commodity hardware and not on an actual NUC, correct? That is not something we support at the moment, although there is a possibility for that in the future. The image may not have the necessary support your specific hardware.