Vbox additions 5.1.22 in CentOS 6 cause display adapter to be "unknown"

[doron]

I've just upgraded vbox from 5.0.30 to 5.1.22. One of my guests runs CentOS (6.3).

After updating the vbox additions in this guest, the first symptom I noticed is that screen resize stopped working (was not reflected in the X server in the guest). I then noticed that the display is recognized as "unknown" (not "vbox"), and all options in "View -> Virtual Screen 1" were greyed out. All in all, it looked as if the graphics driver piece of the vboxadditions is misbehaving or missing, even though the install went smoothly.

I have downgraded the vbox additions in this guest to 5.0.30 - left the host at 5.1.22 - and lo and behold, everything seems to work fine.

I tried a couple of back-and-forth installs of 5.1.22/5.0.30, and it is 100% reproducible.

[Michael Thayer]

Please add a log file for the guest you are running as described on the new ticket page<1>. Please also attach an X server log file from the guest (usually /var/log/Xorg.0.log), the guest's system logs and the output of the commands "lsmod | grep box" and "ps -Af | grep [Bb]ox".

1. https://www.virtualbox.org/newticket