PCI configuration question

[Liu Tao]

Hello all,

In the LinuxBIOS-AMD64 document the author explains the "pci" keyword
 >  The first occurrence of the pci keyword tells LinuxBIOS where the 
bridge device start,
 >  relative to PCI configuration space used by the bridge. The 
following occurences of
 >  the pci keyword describe the provided devices.

then gives an example
 >  northbridge amd/amdk8 "mc1"
 >          pci 0:19.0
 >          pci 0:19.0
 >          pci 0:19.0
 >          pci 0:19.1
 >          pci 0:19.2
 >          pci 0:19.3
 >  end

I'm not clear why the example repeate "pci 0:19.0" three times?
I noticed in chip.c the chip_enumerate() function checks the same path
 >        identical_paths = (i > 0) && (path_eq(&chip->path[i - 1].path, 
&chip->path[i].path));
but I can't find out the real intent.

Another question maybe related to the former one is, in "device" structure
what does the "link[MAX_LINKS]" and "links" member describe?
Does "link[MAX_LINKS]" describes the secondary or subordinate bus of a 
bridge device?
Why MAX_LINKS is defined to 3?

Thanks in advance.