On Mon, 23 Apr 2012, Wang YanQing wrote: > On Sun, Apr 22, 2012 at 08:47:24AM -0400, Alan Stern wrote: > > On Sun, 22 Apr 2012, Anil Nair wrote: > > > > > The port number comes from root hub managed by the host controller. Its > > > fixed dynamically during enumeration, and can change. > > > Please correct me if i am wrong. > > > > You are indeed wrong. Port numbers are not fixed dynamically and they > > cannot change. > Right? Right. > Could you pin out the codes in kernel? I don't understand the question. What code in the kernel do you want to see? > > On the other hand, bus numbers _are_ assigned dynamically and they can > > (and do) change. > > > Indeed, I never meat the situation lspci output different bus number on the same machine. > Any more comment? Try unloading ehci-hcd, uhci-hcd, and ohci-hcd, and then reloading them in different orders. Depending on what sort of hardware you have, the bus numbers will change. On Mon, 23 Apr 2012, Anil Nair wrote: > You meant to say port numbers are fixed but bus address changes > dynamically, also does the host controller > fixes the port number? Yes. > If USB Bus bandwidth is not available, how does it > assign port numbers? The port numbers are determined by the hardware -- each set of wires has its own port number. The numbers have nothing to do with bandwidth. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
