Mint doesn't recognize any display if at boot time there is not a monitor connected.

[ddanesin]

Distribution

Linux Mint 22

Package version

Cinnamon 6.2.9

Graphics hardware in use

No response

Frequency

Always

Bug description

Mint doesn't recognize any display if at boot time there is not a monitor connected.

Steps to reproduce

Start linux mint without monitor or with monitor powered off.
Wait for boot.
Power on the monitor.
Monitor is not recognized, you are unable to interact with the system even if you switch to console (CTRL-ALT-F1 to F7)
You have to reboot the system or connect via lan.

Tried with different hardware the behavior is always the same.

Thanks

Expected behavior

monitor should be discovered as soon as they are plugged.

Additional information

No response

[developer861]

it's not the mint problem i have the same problem it's bios problem i think i found no sulotions for this but you can use hdmi dummy

[ddanesin]

It started happening when I installed mint for the first time, when I had ubuntu this issue was not present.
It happens on a Lenovo ThinkStation P320 with a Intel HD Graphics 630
and on a IBM Think Centre M93p whit an integated graphics on Xeon E3-1200

Thank for the support!
Diego

[komoricodrutz]

This happens also to me on multiple devices across LM generations. I tested some of them also with Windoze and they do NOT exhibit this behaviour. (I have some debian machines and I suppose I can also test it in those conditions). I also have two pfsense instances (yeah, I know, there's no X there) running headless but working just fine if i connect a monitor.
22.2 and 22.3, also an older one with 21.3.
I've noticed this on my media machine as early as 19.x, years ago but as it was usually connected to a TV, it was such a rare occurrence for it to be powered on without it, that I didn't fret about it.
It only works with a dummy plug, but for instance if you have a single display output and need to use a KVM, it kind of defeats the purpose.
With a dummy display (using xserver-xorg-video-dummy driver), i am able to connect to the machine via rustdesk (with linux headless enabled). But connecting a monitor afterwards still won't have any effect.
I suspect that it simply does not initialise the graphics adapter properly if there is no monitor detected. Not tech savvy enough to check this, though.
And as this works fine on other OS-es, it is definitely not a bios setting.
BTW, some of the devices are older NUCs, which have a display emulation setting in the BIOS, precisely for working in headless mode. Still no joy.
I can confirm this behaviour on more machines actually, because I have a couple of friends running mint in a headless/kvm scenario and it is thus consistent across multiple hardware scenarios.
Note: KVM in this context is a KVM switch, not libvirt... :-)
Another small detail: On several laptops, as there is usually always a display connected, this doesn't happen. It immediately reacts to connecting / disconnecting external displays

[teastrainer]

I've got the same Problem in XFCE

System:
Kernel: 6.17.0-14-generic
Distro: Linux Mint 22.3 Zena base: Ubuntu 24.04 noble
Machine:
Mobo: ASUSTeK model: TUF GAMING B450-PLUS II v: Rev X.0x
Graphics:
Device-1: AMD Navi 23 [Radeon RX 6600/6600 XT/6600M] vendor: Tul /
PowerColor Red Devil driver: amdgpu v: kernel arch: RDNA-2 pcie:
speed: 16 GT/s lanes: 16 ports: active: HDMI-A-1 empty: DP-1, DP-2, DP-3,
Writeback-1 bus-ID: 0a:00.0 chip-ID: 1002:73ff class-ID: 0300