On Mon, Jan 25, 2010 at 09:57:45AM -0800, Gary Hade wrote: > On Mon, Jan 25, 2010 at 09:52:37AM +0100, Andreas Besse wrote: > > 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. > > Andreas, Would the physical slot number to PCI ID mapping > provided in /sys/bus/pci/slots by the 'pci_slot' driver possibly > be of any use to you? That mapping should be already there if it is provided by the BIOS. Also, Andreas, I see a symlink for all v4l devices already created in a persistant manner on the more recent udev releases. So you could just use that instead of the "raw" device node, and all should be good. thanks, greg k-h -- 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
