X wont start when a monitor isn't plugged in at boot time

[stephanecharette]

I have a system I use as a file server running Ubuntu 10.04. I don't have a screen hooked up to this system. When this system reboots, if there is no screen, X wont start on it. This then prevents me from using VNC to get to the desktop.

If a monitor is plugged in at the time it boots, then everything works, and I can then remove the monitor. But moving this monitor between computers and crawling under desks is not enjoyable.

How can I fix this so X starts on boot even when no monitor is plugged in?

The error I get in /var/log/Xorg.log* looks like this:

grep -EnC2 "EE|WW|fatal|error" /var/log/Xorg.0.log
...
331- (II) Primary Device is: PCI 01@00:00:0
332- (II) [KMS] Kernel modesetting enabled.
333: (WW) Falling back to old probe method for vesa
334: (WW) Falling back to old probe method for fbdev
335- (II) Loading sub module "fbdevhw"
336- (II) LoadModule: "fbdevhw"
--
362- (II) RADEON(0): Output DVI-0 disconnected
363- (II) RADEON(0): Output DVI-1 disconnected
364: (WW) RADEON(0): No outputs definitely connected, trying again...
365- (II) RADEON(0): Output DVI-0 disconnected
366- (II) RADEON(0): Output DVI-1 disconnected
367: (WW) RADEON(0): Unable to find initial modes
368- (II) RADEON(0): mem size init: gart size :1fdff000 vram size: s:10000000 visible:ffc0000
369- (II) RADEON(0): EXA: Driver will allow EXA pixmaps in VRAM
--
384- compiled for 1.7.6, module version = 2.5.0
385- ABI class: X.Org Video Driver, version 6.0
386: (EE) RADEON(0): No modes.
387- (II) UnloadModule: "radeon"
388- (II) UnloadModule: "exa"
--
390- (II) UnloadModule: "fb"
391- (II) Unloading /usr/lib/xorg/modules/libfb.so
392: (EE) Screen(s) found, but none have a usable configuration.
393-
394: Fatal server error:
395- no screens found

I assume there is something I can edit in /etc/X11/xorg.conf to force it to come up in 1024x768 or some such standard resolution even if no screen is detected. At the moment, that file is very bare with a 3-line "Device", and 3-line "Monitor", and a "Screen" that points to the empty Device and Monitor.

[stephanecharette]

I spent way too much time on this problem over the past few days...but I found the solution. Seems this may be a known issue when working on headless systems. Here is what I did to solve the problem:

1. edit /boot/grub/menu.lst
2. find the line that says:
3. # defoptions=quiet splash
4. change that line to say:
5. # defoptions=quiet splash nomodeset
6. save and exit from the editor
7. run this command: sudo update-grub

Then reboot. Some of this is indirectly mentioned in passing in the Lucid release notes: https://wiki.ubuntu.com/LucidLynx/Re...20architecture though they don't specifically talk about headless systems. And I don't seem to have a /etc/default/grub file, perhaps because this system is an upgrade and not a fresh install of 10.04? Regardless, I hope this helps someone else.

[stephanecharette]

As another possible solution: I converted an old 10.04 desktop to a headless system today, and ran into a similar problem. Wouldn't boot correctly into X after the screen was removed. This is what /var/log/Xorg.0.log ended with:

(EE) May 16 14:08:01 NVIDIA(0): No display devices found for this X screen.
(II) UnloadModule: "nvidia"
(II) UnloadModule: "wfb"
(II) UnloadModule: "fb"
(EE) Screen(s) found, but none have a usable configuration.

The solution to that one was to modify /etc/X11/xorg.conf and add this line:

Option "ConnectedMonitor" "CRT"

to 'Section "Device"' just below the Driver "nvidia" line.

Again, logging it here on the forum in case someone finds this through Google and it helps them out.

[Jumphog]

Thanks for these solutions. Ive just done a fresh install that wouldnt work without a monitor, all this autodetect stuff seems a bit of a step backwards. With the nvidia driver installed and both changes made it'll now get to a desktop without a monitor plugged in.

For info the "ConnectedMonitor" option doesnt work with the fbdev driver, so lucky I had nvidia graphics...

[audiomick]

My thanks too. I have a laptop here with a screen problem. I don't know if I can be bothered trying to do anything with it (it's old, and has had a hard life...) but your solutions may be useful.

[Chaosratt]

I spent way too much time on this problem over the past few days...but I found the solution. Seems this may be a known issue when working on headless systems. Here is what I did to solve the problem:

1. edit /boot/grub/menu.lst
2. find the line that says:
3. # defoptions=quiet splash
4. change that line to say:
5. # defoptions=quiet splash nomodeset
6. save and exit from the editor
7. run this command: sudo update-grub

Then reboot. Some of this is indirectly mentioned in passing in the Lucid release notes: https://wiki.ubuntu.com/LucidLynx/Re...20architecture though they don't specifically talk about headless systems. And I don't seem to have a /etc/default/grub file, perhaps because this system is an upgrade and not a fresh install of 10.04? Regardless, I hope this helps someone else.

Any idea on how to do this with the new Grub 2 install?