Comment # 17 on bug 971907 from Egbert Eich

(In reply to Takashi Iwai from comment #14)
> 
> Yes, there might be other things, and the new config does this so
> intentionally; it's the purpose of the hardening, after all.
> 
> The same issue (VRAM reserved by vesafb) is a long-standing issue, even for
> KMS.  In the case of KMS, the fb switchover happens, so that vesafb leaves
> the resources before the new drmfb takes it again.
> 
> But in the case of vbox...  Well, is vesafb used at all?  If yes, how can it
> keep running while another user-mode driver is running up?

Of course, vesafb is used on VirtualBox in non-EFI mode. All user space drivers
have been running on top of vesafb (or EFI fb). Some ioctl(fd, KDSETMODE,
KD_GRAPHICS) usually convinces the fbdev layer to not paint any more. IHMO,
once this mode is left, the fbdev layer repaints the screen.