ARM server down after monitor removed from HDMI port

I completed the ARM server F35 installation on R Pi 3B+.
I used Cockpit to configure networking, but to operate headless when I removed the external monitor from the HDMI port on R Pi, the server is down and the connection is lost. I have to reboot it. Removal of a USB keyboard is fine.

How can I safely remove the monitor?

Hard to pinpoint which line in the Service logs (Cockpit) shows the underlying cause.

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I don’t know about the R Pi 3B+, however on my 4B I have to boot with the monitor attached, but once it is up and running the monitor can be disconnected. If I have to reboot I have to connect the monitor again.

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I have lines of service logs that are supposed to be linked to disconnected IO devices (HDMI port and USB port). As a result, the Ethernet connection is lost and the server had to be rebooted and relogin.

This may not be enough for me to raise a bug report. For the time being, I’ll leave the monitor connected until the solution is found.

Service logs minutes before REBOOT are as below.

[1636751869.1392] device (p2p-dev-wlan0): supplicant management interface state: disconnected → inactive

[1636751869.1390] device (wlan0): supplicant interface state: disconnected → inactive

[1636751869.1040] device (wlan0): set-hw-addr: set MAC address to 26:3F:34:E3:A8:0C (scanning)


On the Pi 4 I remember that I added hdmi_force_hotplug=1 to /boot/efi/config.txtin order to boot headless. I don’t know if it is still needed, and if for the Pi 3 it is needed too.

I think the change of the HDMI configuration you cited is to fix the Raspberry Pi no display issue, which is different from my case.

Whilst I submitted the soul-crushing bug report with a log file, I wonder if the official Raspberry pi HDMI cable makes any difference. If the bug report is protracting, I will try that to eliminate potential source of problem.

The bugzilla reproduced the issue and is still a problem.

What I did as a workaround as advised by the bugzilla;

  1. In Cockpit, go to terminal and enter systemctl poweroff
  2. Detach the monitor from the HDMI port in RPI
  3. Hard reboot (switch off server and back on)
  4. Wait a few minutes for the server to boot
  5. Log into Cockpit
  6. It works completely headless
    No need to have the monitor connected at all during the boot.