On Tue, 21 Feb 2017, Baolin Wang wrote: > On 17 February 2017 at 16:04, Felipe Balbi <balbi@xxxxxxxxxx> wrote: > > > > Hi, > > > > Baolin Wang <baolin.wang@xxxxxxxxxx> writes: > >>>> (One possible approach would be to have the setup routine return > >>>> different values for explicit and implicit status stages -- for > >>>> example, return 1 if it wants to submit an explicit status request. > >>>> That wouldn't be very different from the current > >>>> USB_GADGET_DELAYED_STATUS approach.) > >>> > >>> not really, no. The idea was for composite.c and/or functions to support > >>> both methods (temporarily) and use "gadget->wants_explicit_stages" to > >>> explicitly queue DATA and STATUS. That would mean that f_mass_storage > >>> wouldn't have to return DELAYED_STATUS if > >>> (gadget->wants_explicit_stages). > >>> > >>> After all UDCs are converted over and set wants_explicit_stages (which > >>> should all be done in a single series), then we get rid of the flag and > >>> the older method of DELAYED_STATUS. > >> > >> (Sorry for late reply due to my holiday) > >> I also met the problem pointed by Alan, from my test, I still want to > >> need one return value to indicate if it wants to submit an explicit > >> status request. Think about the Control-IN with a data stage, we can > >> not get the STATUS phase request from usb_ep_queue() call, and we need > > > > why not? wLength tells you that this is a 3-stage transfer. Gadget > > driver should be able to figure out that it needs to usb_ep_queue() > > another request for status stage. > > I tried again, but still can not work. Suppose the no-data control: > (1) SET_ADDRESS request: function driver will not queue one request > for status phase by usb_ep_queue() call. Function drivers do not handle Set-Address requests at all. The UDC driver handles these requests without telling the gadget driver about them. > (2) SET_CONFIGURATION request: function driver will queue one 0-length > request for status phase by usb_ep_queue() call, especially for > mass_storage driver, it will queue one request for status phase > later. > > So I am not sure how the Gadget driver can figure out that it needs to > usb_ep_queue() another request for status stage when handling the > no-data control? Gadget drivers already queue status-stage requests for no-data control-OUT requests. The difficulty comes when you want to handle an IN request or an OUT request with a data stage. 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
