[Solved] Unable to resize my Linux VM display

[socratis]

Hi,

I recently upgraded from VirtualBox 5 to 6 (6.0.8 on Win 10 x64), and I created a brand new VM with Kubuntu 19.04 x64. But I'm unable to resize the display. Actually, resizing the display from Kubuntu's settings works for a split second, then the screen is back to 800x600.

I found a bunch of previous threads advising to make sure auto-resize is enabled, but here's the thing: it can't be enabled, it's greyed-out (I have a screenshot, but apparently I'm not allowed to link to it and it's > 128KB so I can't attach it either...).
Also greyed-out are the "View => VIrtual Screen 1 => Resize to 1234 x 1234" options. All of them, even the one that's checked (800x600)

I also read that I should use VMSVGA as a graphics controller, which is what I do use... I also assigned the max amount of video memory that VB allows me to (128MB only though, it seems low).

Last but not least, I made sure "maximum gues screen size" (in VirtualBox preferences) is set to "None", rather than the default "Automatic".

What else can I change? Everything worked fine in VB 5, as far as I remember :/


Edit: yup, I just downgraded to 5.2.30, and screen resizing works fine with it

[TomasTX]

I had the same issue - Graphics Controller VMSVGA didn't work. I had to change it to VBoxVGA or VBoxSVGA and both of those work.

[192.168.1.1]

Thank you. I just upgraded again: the machine (which I had created again in VB 5) was by default using VBoxVGA, which indeed works

[socratis]

I have a screenshot, but apparently I'm not allowed to link to it and it's > 128KB so I can't attach it either...

How about shrinking it, resizing it, scaling it, whatever you want to call it?

Also greyed-out are the "View => VIrtual Screen 1 => Resize to

Always prefer to change the VM resolution from within the VM, not from the View menu.

Last but not least, I made sure "maximum gues screen size" (in VirtualBox preferences) is set to "None", rather than the default "Automatic".

You should leave that to Automatic. Change it please...

Edit: yup, I just downgraded to 5.2.30, and screen resizing works fine with it

Then it might be a 6.0.x bug.

I had to change it to VBoxVGA or VBoxSVGA and both of those work.

VBoxVGA is the older model, on the road to be deprecated. VBoxSVGA is for Windows guests, don't use it on Linux guests.

We need to see a complete VBox.log, from a complete VM run, where the problem occurs:

• Start the VM from cold-boot (not from a paused or saved state) / Observe problem / Shutdown the VM (force close it if you have to).
• With the VM completely shut down (not paused or saved), right-click on the VM in the VirtualBox Manager and select "Show Log".
• Save only the first "VBox.log", ZIP it and attach it to your response. See the "Upload attachment" tab below the reply form.

[192.168.1.1]

Always prefer to change the VM resolution from within the VM, not from the View menu.

As I said, I tried that too, which didn't work either (unless you mean yet something else than Kubuntu's settings?)

So, I switched the VM back to VMSVGA, and the issue reappeared. I'm attaching the previously-mentioned screenshot, as well as the log.
During the logged run, all I did was start the VM, go to Kubuntu's settings, try to change the resolution to 1280x768, (see it become larger for a split second then back to 800x600), then close the system normally (via the start menu).

[socratis]

00:00:02.301515 VirtualBox VM 6.0.8 r130520 win.amd64 (May 13 2019 14:14:44) release log
00:00:11.327874 VMMDev: Guest Additions information report: Version 6.0.6 r129722 '6.0.6_KernelUbuntu'

Not only you have an older version of the GAs installed, but you have the ones that came prepackaged with the distro, a fork.

With the VM window having the focus, go to the host's menu "Devices" » "Insert Guest Additions CD Image...". If not prompted by auto-run, run "VBoxLinuxAdditions.run" from the CD. Make sure there are no errors or suggestions during the install. You can safely ignore the "modprobe vboxsf" one.

00:00:02.410986 VRamSize <integer> = 0x0000000002000000 (33 554 432, 32 MB)

The VRAM setting seems too low, increase the VRAM to the max.

00:00:02.410806 NumCPUs <integer> = 0x0000000000000001 (1)
00:00:02.869932 CPUM: Physical host cores: 4

You can definitely afford a 2nd CPU for your guest. Your guest will be thankful...

00:00:02.410864 Path <string> = "E:\DATA\VirtualBox VMs\Ubuntu.vdi" (cb=34)

Just a word of caution; if "E:\" is an external HD and a USB one, you might have significant performance hits, and you got to be extra careful to not lose power or unplug by accident the HD.

[192.168.1.1]

Well that was it, updating the Guest Additions did the trick. I don't remember when was the last time I ever installed them in a VM, that's why I didn't think about them.

About the VRAM, yeah I too thought 32MB was low, but the default value for me was 16MB (despite my GPU having 6GB) so I assumed doubling it was good enough. I had previously also tried with 128MB, which is the max... and also seems low-ish.
E:\ is internal, I have a little mess of partitions
In the end, for what I do, 1 CPU and 32MB of RAM work fine, but yeah if I do more intensive stuff I'll add more

[socratis]

despite my GPU having 6GB

Your GPU's VRAM is not used, your VM uses a virtual, limited GPU.

Well that was it, updating the Guest Additions did the trick

Glad you got it going. Marking as [Solved].