i810/i915 showing two PCI BusIDs

[Matt Hempel]

I have a working dual-head configuration on a Dell M140 laptop using the 
i810 driver.  My LCD is on Pipe A, my external CRT on Pipe B.  No DRI, 
unfortunately, because I'm using Xinerama but otherwise, everything is fine.

However, Xorg reports two BusIDs on startup and I'm clueless as to what 
the second one is:

(II) Bus -1: bridge is at (0:31:0), (0,-1,-1), BCTRL: 0x0008 (VGA_EN is set)
(--) PCI:*(0:2:0) Intel Corporation Mobile 915GM/GMS/910GML Express 
Graphics Controller rev 3, Mem @ 0xdff00000/19, 0xc0000000/28, 
0xdfec0000/18, I/O @ 0xeff8/3
(--) PCI: (0:2:1) Intel Corporation Mobile 915GM/GMS/910GML Express 
Graphics Controller rev 3, Mem @ 0xdff80000/19

There's only one graphics card in this laptop, unless I'm missing 
something.  My Device sections reference 0:2:0 only and it doesn't seem 
to have anything to do with pipes.  Does anyone know what the second 
BusID represents?

Appreciated

--matt