Problems with CustomVideoMode

[tr909virtualbox]

Hi all,

I'm experiencing a problem and am banging my head against the wall for several hours. I hope, you could help.

I'm trying to set a customvideomode, so that I can use my whole laptop screen resolution (1280x800x32) for a guest, which is not supporting guest additions. Unfortunately, the custom video mode is not passed through and is automatically removed from the vbox file.

In detail:
1. I'm switching off the VM and also VirtualBox Management Console.
2. vboxmanage setextradata "VMnName" "CustomVideoMode1" "1280x800x32"
3. Copy *.vbox file and rename the copy to *.xml
4. Open the *.xml file to check, that the changes are set. Everythin fine. The customvideomode is set
5. Start the VM
6. Check with boot loader the video modes or boot the guest with dedicated Video Mode will not work either
7. While the VM is running, I copy the *.vbox file again and rename the copy to *.xml
8. Open the "new" *.xml file... -> the extradata customvideomode is gone with the wind?!?!?
9. A look into the logs didn't get me a clue. The only thing I found was:

00:00:01.134 [/Devices/vga/0/Config/] (level 4)
00:00:01.134 CustomVideoModes <integer> = 0x0000000000000000 (0)
00:00:01.134 FadeIn <integer> = 0x0000000000000001 (1)
00:00:01.134 FadeOut <integer> = 0x0000000000000001 (1)
00:00:01.134 HeightReduction <integer> = 0x0000000000000000 (0)
00:00:01.134 LogoFile <string> = "" (cb=1)
00:00:01.134 LogoTime <integer> = 0x0000000000000000 (0)
00:00:01.134 MonitorCount <integer> = 0x0000000000000001 (1)
00:00:01.134 ShowBootMenu <integer> = 0x0000000000000002 (2)
00:00:01.134 VRamSize <integer> = 0x0000000008000000 (134217728)

10. Banging my head against the wall for the next time
11. loop

Additional information: Predefined Video Modes are working well. Unfortunately, 1280x800 is not a predefined mode.

Does anyone has an idea, why the extradata is removed from the vbox settings file without further notice?!

Or does anyone knows, how to accomplish this goal?

Cheers,
Daniel

[Davy Bartoloni]

Take a look at: http://forums.virtualbox.org/viewtopic.php?f=22&t=31104

(probably VB is still running when you try to change/replace the XML file)

[tr909virtualbox]

Hi all,

thanks for your hint. But that didn't help.

I tried something else, which helped. I restricted the access to the vbox file, that no one have write access to it. Et voila, the custom video mode was present and was also passed trough to the guest.

But the question still remains, what is the root cause is...
It seems, that virtual box somehow alter the vbox file, when starting the VM and removes the CustomVideoMode. But why? Bug or feature?

Any suggestions?

Slainte,
Daniel