On Wed, 18 16:58 , Peter Stuge wrote: > > Again, the root hub is not a USB device, but an implementation-specific > part of the host controller. The root hub thus doesn't have USB VID/PID. > > If the HC is on a PCI bus then it will have a PCI VID/PID, but > pretending that those are USB ids is a bad idea, since they are two > unrelated namespaces. > > Consider a PCMCIA (not CardBus) USB host controller. There you would > only have PCMCIA ids to go on. Another unrelated namespace. Bad idea > to mix with USB ids.
I see your point. Particularly for NEC, which have a PCI ID of 0x1033 assigned to them, while their assigned USB PID is 0x0409. The distracting thing is that 1033 == 0x0409. The Windows System Information reports the uPD720200 HC (driver 2.1.36, FW 4015) as PCI\VEN_1033&DEV_0194, and its root hub as NUSB3\ROOT_HUB30&VID_1033&PID_0194. The PID resolves to "Nucam Corp." in libusbx, which is plain wrong. Intel, for example uses PCI\VEN_8086&DEV_1D2D on a HC and Windows reports USB\ROOT_HUB20&VID_8086&PID_1D2D for the root hub. Well, Intel owns both the 0x8086 PCI and USB ID, so the result is ok. Still, the PID is likely not to exist at all. As for the VID/PID for root hubs provided by libusbx, I'd consider it unsafe to rely on this information. I'm a bit clueless currently how to resolve this in a sane way. Of course I could use prior knowledge about the fact that these IDs are PCI ones in reality, to look them up in pci.ids. But that's not a real solution. Amongst others since they could be something different from PCI in the first place. Any opinions except "don't look at root hubs at all"? > I think that HCs and root hubs should not be exposed as USB devices, > because they are not USB devices. As for the root hubs, I agree with Pete; however, the VID/PID assignment has to be thought through since it won't be correct in most cases (i.e. if the PCI and USB VID are not identical for a given manufacturer) All the best, /Markus ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ libusbx-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libusbx-devel
