Boot with a screen plugged in, but won't boot with no screen attached...

[freefallvibe]

Hi!


I've build a rig a few months ago. I'm running Kubuntu on it (used to be on Ubuntu) and plan to use it for some virtualization and other purposes. I had planned not to have any screen hooked to it.


While installing, the rig was plug on a tv screen (in the family room) trough an HDMI cable while I was setting it up. Often, I didn't use the tv (since other wanted to watch TV, it was still connected to it) and connected trough SSH and VNC.


I went on to move the rig to another place in the house and from that point on, I couldn't log in to the machine anymore. The only thing that had changed was that I didn't have a screen hooked up anymore. I brought a screen to it, and then I was able to boot.

So to sum it up.
Screen plugged in = Boots normally, able to login via SSH and VNC.
Screen unplugged = Unable to ping the machine, or SSH into it.


I booted the pc with the screen unplugged waited 2 min then plugged one in (tried both VGA and HDMI) to see what might the problem, but I can't see anything, actually, the screen goes to sleep.


I'm at a point where I wander if it's a BIOS setup problem or Kubuntu boot up.



I tried to find something in the BIOS that would be obvious, but was not successful. Does someone has any idea what the problem could be?


ASUS Micro ATX DDR3 2600 LGA 1150 Motherboards Z97M-PLUS
Intel Core i7-4790S Processor (8M Cache, 3.2 GHz) BX80646I74790S
Kingston HyperX FURY 16GB Kit (2x8GB) 1866MHz DDR3 CL10 DIMM - Black
Samsung XP941 256GB PCIe 2.0 x4 M.2 SSD MZHPU256HCGL
2 SATA drive

Thanks in advance!

[SteveRiley]

Googling for "computer won't boot without monitor" shows some potentially promising results. I'm somewhat surprised -- I didn't even realize this was a thing.

[oshunluvr]

Look at your /var/log/Xorg.0.log for failures (EE) at the end. Likely, it's because you're trying to start a GUI desktop without a monitor to display it on. Try "nomodeset" in your boot options or 'Option IgnoreEDID' "true" in xorg.conf if you're using one.

Also, BIOS might have a "stop on" group of options that might include keyboard and monitor.

[freefallvibe]

Look at your /var/log/Xorg.0.log for failures (EE) at the end. Likely, it's because you're trying to start a GUI desktop without a monitor to display it on. Try "nomodeset" in your boot options or 'Option IgnoreEDID' "true" in xorg.conf if you're using one.

Also, BIOS might have a "stop on" group of options that might include keyboard and monitor.

Thanks for the tip. I checked the Xorg file and there seems to be error. I tried the option of nomodeset, but unfortunately it doesn't work; If I power on the rig with no screen plugged in, nothing I hear the sound of HD working for a few sec, but then nothing. I tried to login via SSH, nope connection, can't ping the machine.

I guess I'll have to check with Asus, maybe there's something I'm not seeing in the BIOS; I believe I checked every single line of it for an option about Alt-ON.. no luck..

[Snowhog]

Found on Ubuntuforums, and while it is old, it might shed light on your issue and suggest a solution.

http://ubuntuforums.org/showthread.php?t=1466271&page=2

[freefallvibe]

Thanks Snowhog.

I tried several variation of the solution (I had already tried a similar solution) and have encountered other problems or was simply not working.

I got fed-up. I decided to look for a permanent solution that would not be affected by future update of the OS; an emulator or an actual screen. Verdict, I ordered a small 7 inch screen with a 1280 x 800 resolution with VGA and HDMI port. Once in the rack, it will be easier to troubleshoot before the OS if need be.