On Fri, Feb 19, 2010 at 04:49:13PM +0530, Rajat Jain wrote: > Assuming the firmware has not done any PCI bus enumeration in a system > with 2 PCI controllers, I want to know if PCI bus numbering done by > Linux WILL have bus numbers repeated (among the 2 PCI trees). > > For instance: > > 1) Will the bus emanating from both the PCI bus controllers have PCI bus > no 0 (although they will have different PCI domain numbers). That's up to the hardware / firmware involved. For example, large HP Itanium systems have multiple IO chassis. Each chassis contains around 8 PCI host bridges, which may be numbered along these lines: 0x00 0x20 0x40 0x60 0x80 0xa0 0xc0 0xe0 So there will not be duplication of PCI bus numbers if you have only one chassis, despite there being multiple PCI root bridges. When you plug in a second chassis, the same bus numbers exist in that chassis too, and the only way to distinguish between them is by domain number. I believe other high-end systems operate in much the same manner. -- Matthew Wilcox Intel Open Source Technology Centre "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step." -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
