2D Rendering is broken: Debian 10 VM

[Technologov]

For some (unknown) reason, it seems like VM-SVGA card is totally broken, at least for Debian 9, 10 and 11 guests (with KDE/X11 configured).

For Debian 9/10/11, auto-start of X11 is broken, and for Debian 10, even manual start of X11 results in display garbage.
Those Debian VMs were installed manually, not via "unattended" script, with X11 + KDE setup, as I would do on my physical desktop.

Is it possible to Vbox-tools from debian repo got auto-installed somehow ? (I did NOT install Vbox GA here)

What could have causes it ? Either broken GA (that are part of Debian ?) -- or a broken FPU / CPU virtualization ?

Fresh Debian 10 has two suspecious modules loaded, that I have never installed: "vmgfx" and "vboxguest".
According to "session information", Debian 10 comes pre-loaded with VBOx GA v5.2.0.

If VirtualBox hardware changes in an incompatible way (with older VirtualBox or with VMware), then it is suggested to create a new device PCI ID, so that old drivers are NEVER EVER used on it. Then users will be forced to install new drivers / new VBox GA. But will not have such massive graphics glitches / rendering problems.

see rendering garbage of Debian 10 + X11 + KDE here:
https://www.dropbox.com/s/xbs4yzohagvt8 ... _59_27.png

[ajgringo]

For some (unknown) reason, it seems like VM-SVGA card is totally broken, at least for Debian 9, 10 and 11 guests (with KDE/X11 configured).
Fresh Debian 10 has two suspecious modules loaded, that I have never installed: "vmgfx" and "vboxguest".
According to "session information", Debian 10 comes pre-loaded with VBOx GA v5.2.0.

Those modules are part of the GA installation. I would remove the Debian packages and install the version from your host's GA ISO. My Debian 10 w/LXQT runs without a hitch.