Intel CONTROLLERS 413808 - Manual (Page 288)

Intel
®
413808 and 413812—Address Translation Unit (PCI Express)
Intel ® 413808 and 413812 I/O Controllers in TPER Mode
Developer’s Manual October 2007
288 Order Number: 317805-001US
3.15 Root Complex Functionality
The 4138xx does not support Root Complex.
3.16 Embedded Bridge Functionality
Note: Not supported on 4138xx.