On 06/26/2013 12:37 PM, Bjorn Helgaas wrote: > > Yeah, that's what I was thinking. > > But Peter's comment makes more sense to me now. The spec refers to > that config register as "Subsystem ID," not "Subsystem Device ID," but > I was confused because most existing usage treats it as a device ID. > For example, the field in struct pci_device_id is named "subdevice," > and all the existing #defines in pci_ids.h are of the form > PCI_SUBDEVICE_ID_*. > > Device IDs are pretty specific identifiers, so I was thinking that a > "sub-device ID" would be even more specific. Then it would make no > sense to have a "sub-device ID" that was as generic as "MINNOWBOARD." > But the register is actually *not* a "sub-device ID," and I can see > that using the same Subsystem ID for all the devices on a board might > make sense. > Subsystem IDs is basically a board ID in the traditional PC view, but they didn't call it that because it would have been confusing in other, nontraditional configurations. Microsoft has a "best practices" document, which may end up becoming basis for a future PCI-SIG document clarifying the standard: http://msdn.microsoft.com/en-us/library/windows/hardware/gg463287.aspx -hpa -- 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
