Auto-resize Guest Display and Seamless Mode does not work -> configuration issue

[wojciech]

Environment:

Host:

• OS: Windows 7 release 6.1.7601 Service Pack 1

Guest:

• OS: Ubuntu 18.04.1 LTS (xubuntu-18.04.1-amd64)
• Linux kernel: vmlinuz-4.15.0-45-generic
• Platform: x86_64
• Desktop: xfce4 4.12.4

VirtualBox:

• Version: 5.2.26 r128414 (Qt5.6.2)
• Extension Pack Version: 5.2.26r128414

CAUTION:

I am posting this ticket for information purposes, to save time of people who have "nomodeset" kernel parameter in their grub.cfg

2 weeks ago "Auto-resize Guest Display" and "Seamless Mode" worked fine, but last week something has changed. I could not pin-point the source of problem for couple days, I remember I installed ubuntu updates as usual and after starting VBox the next day both modes became grayed out in "View" menu.

I tried to solve the problem using tips found on VBox forums:

1) Installed new VBox with guest additions - it did not help.

2) I set "Maximum Guest Screen Size" to "Automatic" in File > Preferences ... > Display tab - it did not help.

3) I tried to trigger the guest system to switch to a particular resolution by sending a video mode hint using the VBoxManage tool.

I opened cmd.exe in Windows and did the following:

cd C:\Program Files\Oracle\VirtualBox\

VBoxManage.exe controlvm xubuntu-18.04.1-amd64 setvideomodehint 1920 1080 32

but inside VBox.log I saw just a single event:

VMMDev: SetVideoModeHint: Got a video mode hint (1920x1080x32)@(0x0),(1;0) at 0

of course guest screen resolution did not change.

4) Finally I set the GRUB_GFXMODE to 1280x1024x32 in GRUB and booted ubuntu, the guest screen became big enough to work on it, but "Auto-resize Guest Display" and "Seamless Mode" still did not work.

I started GRUB in commad-line mode to see what video modes (resolutions) are supported by graphic adapter:

grub> hwinfo

or

grub> vbeinfo

From available modes I choose 1280x1024x32

Then I booted the ubuntu and created a new grub.cfg:

# vim /etc/default/grub

GRUB_GFXMODE=1280x1024x32
GRUB_GFXPAYLOAD_LINUX=keep

# grub-mkconfig -o /boot/grub/grub.cfg

at this moment I noticed that I have "nomodeset" kernel parameter in GRUB_CMDLINE_LINUX. After removing it and recreating grub.cfg I booted ubuntu one again, when Xfce login window was displayed the "Auto-resize Guest Display" and "Seamless Mode" menu item become available.

[Michael Thayer]

Is it alright if I close this as "not a bug"? It will still stay in the bug tracker and be findable by search engines.