On Tue, 21 Feb 2017, Baolin Wang wrote:
On 17 February 2017 at 16:04, Felipe Balbi balbi@kernel.org wrote:
Hi,
Baolin Wang baolin.wang@linaro.org 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