Screen resizing in various VMs

Discussions about using Linux guests in VirtualBox.
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FX8370core
Posts: 10
Joined: 16. Feb 2021, 20:54

Screen resizing in various VMs

Post by FX8370core »

Host: Devuan Chimaera, kernel 5.14, VBox 6.1.30

Guest1: Debian 11 Bullseye w/Mate desktop, kernel 5.14, graphics VMSVGA 48 MByte, latest guest additions installed
Guest2: Devuan Daedalus w/KDE Plasma desktop, kernel 5.15, graphics VMSVGA 48 MByte, latest guest additions installed

On both VMs when trying to set the screen size to 1920x1200, this is being reset to 800x600 after a few seconds. Can't figure out why. Don't see an error message in the log. Attached the one from Bullseye shortened to a size that can be loaded.

Thanks for useful hints....

FX
Attachments
Bullseye-VBox.log
Log from the Bullseye VM
(101.06 KiB) Downloaded 6 times
scottgus1
Site Moderator
Posts: 20965
Joined: 30. Dec 2009, 20:14
Primary OS: MS Windows 10
VBox Version: PUEL
Guest OSses: Windows, Linux

Re: Screen resizing in various VMs

Post by scottgus1 »

Regrettably, you shortened all the important parts...
Zipped logs fit. Please try again.
FX8370core
Posts: 10
Joined: 16. Feb 2021, 20:54

Re: Screen resizing in various VMs

Post by FX8370core »

Here are the zipped Logs from both VMs.

FX
Attachments
Daedalus-VBox.log.zip
(44.27 KiB) Downloaded 7 times
Bullseye-VBox.log.zip
(40.99 KiB) Downloaded 6 times
scottgus1
Site Moderator
Posts: 20965
Joined: 30. Dec 2009, 20:14
Primary OS: MS Windows 10
VBox Version: PUEL
Guest OSses: Windows, Linux

Re: Screen resizing in various VMs

Post by scottgus1 »

Both VMs have good Guest Additions installed. Both video RAM settings are 48MB. Try sliding each VM's video RAM to max. Else look in the VM OS config files that might be limiting screen size (what, I don't know, though).

I doubt it's Virtualbox limiting the size, because the VMs used 1024x768 before GAs were installed, which is above 800x600. But check the main Virtualbox window File menu, Preferences, Display to see if a limit has been placed.
FX8370core
Posts: 10
Joined: 16. Feb 2021, 20:54

Re: Screen resizing in various VMs

Post by FX8370core »

Strangely enough, got a VM with Devuan Daedalus (~Debian Bookworm/Testing w/o systemd) with Mate desktop working alright with identical settings (ar least I can't find any difference). This VM is based on an upgrade from Devuan Chimaera (~ to Debian Stable/Bullseye w/o systemd). When logging in, the screen is drawn to the desired size of 1920x1200. 2-3s later the screen flickers again, but the size remains as is. Shutting down and restarting preserves the size.

Could fix the Bullseye VM. Doubled the main memory to 4G, screen memory to 256M, tried VboxSVGA, went back to VMSVGA, and finaly found that Nested VT-X wasn't ticked. Enabled this box and the VM since then seems to be satisfied with a screen size of 1920x1200. When logging in, the screen is drawn to the desired size of 1920x1200. 2-3s later the screen flickers again, but the size remains as is.

Last problem: the Devuan Testing/KDE VM: also moved the main memory to 4G, screen memory to 128M (why is the max different to the Bullseye VM?), tried VboxSVGA, went back to VMSVGA: as soon as I ticked apply in KDE screen resizing, the VM jumped back to 800x600. Finally found an internal setting for OpenGL, set that from 2.0 to 3.1, and now the VM stays at 1920x1200. Strange behaviour, didn't see that before.

Will wait a few restarts before I say its fixed ....

FX
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