[openfirmware] Can't get /pci/display ihandle under vbox&laptop

[胡松涛]

Hi,

When I learn http://www.openfirmware.org/1275/practice/#graphics
   I found that: I Can't get /pci/display ihandle under vbox, when I boot  
up with usb-disk on my laptop, I can't get ihandle as well.

but I can get /pci/vga ihandle under qemu. And it works fine with  
graphics.