Hi: 2010/2/19 Greg KH <greg@xxxxxxxxx>: > On Fri, Feb 19, 2010 at 10:14:57PM +0800, vichy wrote: >> Dear all: >> I am quite curious about how the control pass from ehci to uhci/ohci >> or control pass from uhci/ohci to ehci when I plug fs/hs device at the >> same port? > > It is described in the usb spec, hopefully :) As far as I know, ehci define the port routing method, and it will pass the control to the companion controller by port owner bit in port status and CF flag in register. does that mean once we set the PORT_OWNER bit in port it will wake up the uhci interrupt? > >> As I know, ehci and uhci/ohci will first register their pci drivers at >> module init call. >> Then the interrupt of uhci will keep happening. > > What do you mean by this? I add print message at usb_hcd_irq to show up the product_desc. and it will keep showing "UHCI Host Controller", which we define in uhci driver. > >> My questions are: >> 1. why the interrupt of uhci keep happening, is that defined in uhci spec? > > What do you mean by "keep happening"? I say this by what I ovserved above. > >> 2. both ehci and uhci register the same irq# and same irq function, >> usb_hcd_irq, how os know to pass the correct hcd when irq happen? > > The driver can determine which interrupt really was for it. It's a > sharred interrupt line, quite common. I saw the irq flag we set is shared. But what make me curious is when calling usb_hcd_irq, os will pass ehci hcd or uhci hcd. how os know which hcd it shoud pass to usb_hcd_irq? > > I'm confused as to the exact problem you are trying to resolve here. > > thanks, > > greg k-h > thanks for your help, vichy -- 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
