On Tue, 2008-11-11 at 09:10 -0800, Jesse Barnes wrote: > On Monday, November 10, 2008 10:04 pm Benjamin Herrenschmidt wrote: > > Hi Jesse ! > > > > Any reason why we don't create the legacy_io/mem files for child > > busses ? > > > > The fact that they only exist for PHBs makes it tricky for userspace > > programs to find them > > > > Since they only appear in /sys/class/pci_bus/* which has no hierarchy > > information, a user space program like in my case that gets passed a > > sysfs path to a device, would have to walk back up the chain to find out > > the phb in order to then find it in there. > > Yeah, in that case it's a bit more of a pain to find. Originally though we > figured that the legacy spaces were per-domain or host bridge resources, so it > didn't make sense to propagate them down to child busses. If that's not the > case for your platform it probably makes sense to let them trickle down. They are per domain. It's just that it makes it more painful for userspace to find them if they aren't everywhere. Especially on PCIe where there's generally a P2P bridge at the root of everything. > I'd have to go make sure the code does the right thing for child buses on > ia64... /me checks. I think base ia64 will be ok, but whether sn works would > depend on how the PROM fills in the legacy_mem address (i.e. it should work > but would need testing). Or you can internally make it walk up to the PHB ... Cheers, Ben. -- 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
