On Tue, Dec 07, 2010 at 06:41:22PM +0000, Ben Hutchings wrote: > On Tue, 2010-12-07 at 12:19 -0600, Matt Domsch wrote: > > On Tue, Dec 07, 2010 at 06:16:22PM +0000, Ben Hutchings wrote: > > > It appears that 'unknown slot' is treated as a specific slot and all > > > devices with an unknown slot are given unique indices. Perhaps this > > > doesn't matter in the end, since no name is generated when the slot is > > > unknown. > > > > Yes on all counts. > > > > > However, the 2 NIC ports do have their own indices (specified with the > > > dev_id attribute) and it should be possible to distinguish slots by > > > PCI/PCIe topology even though the name given won't correspond to any > > > markings on the motherboard. > > > > Tell me more about the dev_id attribute. I'm happy to use it, but I > > don't understand the rules around populating it. > > As I understand it, dev_id is supposed to distinguish net devices > corresponding to multiple ports on a single network controller. > However, a value of 0 could mean either 'unspecified' or 'first port' so > you would have to verify that multiple net devices for the same slot > have unique dev_id values before taking them into account. Only a handful of drivers seem to populate dev_id that I can find: [drivers/net]$ grep -r -- '->dev_id' * cxgb4/t4_hw.c: adap->port[i]->dev_id = j; mlx4/en_netdev.c: dev->dev_id = port - 1; sfc/siena.c: efx->net_dev->dev_id = EFX_OWORD_FIELD(reg, FRF_CZ_CS_PORT_NUM) - 1; My test system has none of these, so dev_id does have the expected value of 0 for all ports, same card or whatever, but in all of these drivers appear to use 0 to mean first port too. So, I'm not sure how useful this field is in practice today. Right idea though... Thanks, Matt -- Matt Domsch Technology Strategist Dell | Office of the CTO -- To unsubscribe from this list: send the line "unsubscribe linux-hotplug" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
