Andreas Besse wrote: > Greg KH wrote: > >> On Fri, Jan 22, 2010 at 06:34:51PM +0100, Andreas Besse wrote: >> >> >>> Hi, >>> >>> I observed that the PCI Bus id's of the onboard network cards changed >>> after I added a PCIe Dual DVB-Card to my system. >>> >>> The ID's changed from 02:00.0, 03:00.0 (see lspci_with_dvb.txt) to >>> 03:00.0, 04:00.0 (see lspci_with_dvb.txt) >>> >>> How is the ordering of PCI/PCIe devices determined in generally by the >>> linux PCI subsystem? >>> >>> >> Totally random, depending on the phase of the moon, and the location of >> your computer in relation to the nearest large body of water. >> >> Seriously, this is expected, you can not rely on pci bus ids to remain >> constant, especially if you have changed the physical system (like >> adding a card which you did.) >> >> >> >>> is the Bus ID for a specific PCI/PCIe Slot deterministic at every boot >>> if no hotplug (removing or adding PCI/PCie cards) is involved? >>> >>> can I assume that the Bus ID's don't change if I don't add or remove any >>> PCI/PCie cards? >>> >>> >> Nope, I have a machine here that will reorder things every 4th boot or >> so. It's a "feature" of the BIOS according to the bug I filed with the >> manufacturer that they closed out as invalid. >> >> > do you have a link to the bug report? > >> So never rely on these ids, they can not be guaranteed to be stable, and >> will not be. >> >> > If PCI bus IDs are not usable, what other mechanisms do exist for > knowing which particular physical hardware device (plugged into a > PCI/PCIe slot) is assigned to which particular Linux device ? > > I want to identify a DVB S2-Card which is plugged into a specific > PCIe-Slot by a udev rule and assigns a specific linux device (e.g. > /dev/dvb/adapter0). > sorry my statement is a bit ambiguous. For a single card there is no issue, but for multiple cards of the same type. If multiple DVB cards of the same type, but with different signals/cables are used, the cards need to identified. > Does the behavior you described with your board exist with all boards? > > If yes, I wonder how Linux can at all be used for any reliable hardware appliance, which includes two identical PCI boards, which need to be distinguished due to different signals/cables being connected to each board. > > regards, > Andreas Besse > > -- 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
