On Tue, Oct 12, 2010 at 09:55:29AM -0400, Alan Stern wrote: > On Tue, 12 Oct 2010, Brokhman Tatyana wrote: > > > Hi Alan > > > > Thanks you for your comments. Please see my reply inline. > > > > In addition, I suspect the dummy_hcd driver structure shouldn't contain > > > an address_device entry. It should be present only in dummy_ss_hcd. > > > > I'm not sure I follow... > > According to the code and comments in hub.c address_device cb is used if > > the host controller wishes to choose the device address itself instead of > > the address chosen by the core. > > Correct. > > > It seems to me that there is nothing > > preventing the dummy_hcd from supplying such cb as well. Is there? > > Having both HS and SS dummy_hcd determine the device address seems more > > convenient for testing proposes. > > For testing purposes, it is best to imitate the behavior of a real > device as closely as possible. USB-2.0 host controllers do not assign > their own addresses to devices; they use the addresses provided by > usbcore. I think this is also true for the low/full/high-speed > components of a USB-3.0 controller. There is only one controller, the xHCI controller, that handles all device speeds. There are no companion controllers for a USB 3.0 host controller. The xHCI host controller uses the hardware assigned address for all devices (LS/FS/HS/SS), not the usbcore address. But I'll admit I don't understand what dummy-hcd is supposed to do, so I'm a bit confused as to why it needs an address_device function. Is it supposed to be the gadget-side interface to the hardware that's transmitting over USB (i.e. responding to the USB host)? Or does it have something to do with a gadget switching over to host mode for OTG? Sarah Sharp -- 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
