Ticket #14882 (new defect)

Opened 4 years ago

Last modified 4 years ago

Windows not shown with Seamless mode if launched headless

Reported by: DaVinci Owned by:
Component: GUI/seamless Version: VirtualBox 5.0.10
Keywords: Cc:
Guest type: Linux Host type: all


If a vm is started headless and the seamless attribute is enabled, when you switch to the VM, the windows are not actually shown. They are visible in preview. It has been suggested that switching from headless to seamless is not supported functionality, but there are no warnings about it's unsupported nature nor an error message when you try and do it. Nothing crashes, it just does not work as expected, though it would be really handy if it did. Example Video's Seamless: Headless to Seamless: Detachable to Seamless:

Change History

comment:1 Changed 4 years ago by frank

  • priority changed from blocker to major

comment:2 Changed 4 years ago by DaVinci


Thanks for taking a look at this. Do you have any initial thoughts? Is this likely to get fixed in the next 2 to 3 months?

comment:3 Changed 4 years ago by frank

It does not make sense to switch a headless VM into seamless mode. Headless mode means that there is no frontend for this VM. Therefore it's a bug that this VM starts fine but invisible in seamless mode. The fix is to prevent that or perhaps automatically switch back from seamless mode to normal mode if a VM was started with the normal GUI, then saved, and now started headless.

This is something which should be fixed like I sketched above but I cannot promise any ETA.

comment:4 Changed 4 years ago by DaVinci

The desire to switch from headless to seamless comes from the want for the initial OS loading screens to be hidden. I can make a custom kernel and pretty much take total control of the guest startup process with a custom embedded version of linux, but I don't have that much control over virtual box. I can get from the bios to the browser without making any new displays, and in short order. It looks awesome seamless. How would I get rid of the initial non-seamless displays?

comment:5 Changed 4 years ago by DaVinci


I appreciate any attention you can provide to this issue.

Best Regards, Donald A. Cupp Jr.

comment:6 Changed 4 years ago by frank

Not sure if I understand your question correctly. You should definitely not use the seamless mode to hide some guest output. The VBox splash screen can be disabled by VM configuration. And if you have full control over the guest then better prevent the guest from generating any output during boot.

comment:7 Changed 4 years ago by DaVinci

Removing the Virtual Box splash was straightforward. Once the kernel starts, I can control the guest screens, but prior to that point I can not. When I want to run a vm in seamless mode, I have to start the VM, and all of the following happens

  1. A VM Console appears on the screen
  2. The ISOLINUX Copyright notice is displayed( I could go with EFI, but it actually takes longer to boot)
  3. X starts and clears the screen
  4. VBox guest starts seamless mode, and everything disappears
  5. The X windows application starts and is displayed as if it was a native application( Seamless like we like it )

When the application is closed,

  1. X shutsdown
  2. The VM console reappears
  3. The VM shutsdown, and the console disappears

The challenge that I can not solve is how to hide the elements 1,2,3 and 7 from above. I thought starting headless was a path, as it does hide 1,2 and 3 and if I could switch back and forth, could hide 7, but right now it is also hiding 5 which is pretty important.

comment:8 Changed 4 years ago by DaVinci

Post holiday bump, welcome back. Frank, do you see what I am trying to accomplish/think it is possible?

comment:9 Changed 4 years ago by DaVinci


Are you still considering this? Is there anything I can do to move you in my direction?

Best Regards, Donald A. Cupp Jr.

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