Reboots without attached monitor

[meyergru]

Wow. You won't believe this - I at least would not, had I not seen it myself.

I moved a Topton N5105-based system (I wrote about this https://forum.opnsense.org/index.php?topic=27938) from my office to the would-be location, only to find out that the unit resets itself every 5 minutes. This behaviour is consistent and reproducable.

Since it worked without a hitch at the office, I wondered what causes this and to my great surprise, the reason is that I attached no monitor at the new location. This was really hard to find out with no log entries whatsoever and whenever I looked at the console (attaching a monitor), nothing happened.

The HDMI cable has to be plugged into a display that is turned on for the problem not to occur. When I turn the display off, the problem is as without any display. From the looks of it, I would assume that just when the screen should go blank (i.e. after 5 minutes), the system just reboots when no active display is attached, like "duh, I cannot blank a non-existent display".

I know this does not happen on similar X64-based systems I have, so there must be a BIOS bug (it has an EFI firmware) or an incompatibility to OpnSense/FreeBSD.

I already tried to set the console to "Mute console", "None", disabled the VT driver to no avail. I know that there are images for serial-only installation, I wonder if that helps?

Is there an easy way to have the system act as if it was installed from the "serial" image, thereby disabling any video drivers that may be active and try to blank the display? Or can I disable blanking, maybe with some tuneable?

[meyergru]

I found a band-aid for the problem. Add this line to /etc/rc.conf:

Code: [Select]

blanktime="NO"

The default screensaver inactivity timeout was indeed 300s as I guessed, and the line above fixes the problem for me.

I also contacted both Topton and the manufacturer of the motherboard, Changwang about this being most probably a firmware bug.