Comment # 11 on bug 63865 from Alex Deucher

(In reply to comment #9)
> The issue can be reliably reproduced on my E-450. I bisected it to:
> 
> ----------
> commit f9a37be0f02a943d63e3346b19f9c9d8d91826cb
> 
>     x86: Use PCI setup data
>     
>     EFI can provide PCI ROMs out of band via boot services, which may not be
>     available after boot. Add support for using the data handed off to us by
>     the boot stub or bootloader.
> ----------

The version grabbed from boot services hasn't been patches by the sbios yet so
it's not usable by the driver.  Macs need the boot services copy since they
don't provide a way to access it after the OS loads.  On non-Macs we have a
method to fetch the proper vbios via acpi so we don't need this.