Re: [PATCH] usb: dwc3: ep0: Fix the possible missed request for handling delay STATUS phase

From	Felipe Balbi <balbi@kernel.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH] usb: dwc3: ep0: Fix the possible missed request for handling delay STATUS phase
Date	2017-02-28 13:10 +0100
Message-ID	<tfOLo-4dY-9@gated-at.bofh.it> (permalink)
References	<tfBO9-3yE-1@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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Hi,

Alan Stern <stern@rowland.harvard.edu> writes:
>> 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.

I don't see a difficulty there. Gadget driver will see wLength and
notice it needs both data and status stages, then it does:

usb_ep_queue(ep0, data_req, GFP_KERNEL);
usb_ep_queue(ep0, status_req, GFP_KERNEL);

Just needs to prepare both requests and queue them both ahead of
time. UDC drivers should hold both requests in their own private list
and process one at a time.

-- 
balbi

Thread

Re: [PATCH] usb: dwc3: ep0: Fix the possible missed request for  handling delay STATUS phase Baolin Wang <baolin.wang@linaro.org> - 2017-02-17 06:50 +0100
  Re: [PATCH] usb: dwc3: ep0: Fix the possible missed request for handling delay STATUS phase Felipe Balbi <balbi@kernel.org> - 2017-02-17 09:10 +0100
    Re: [PATCH] usb: dwc3: ep0: Fix the possible missed request for  handling delay STATUS phase Baolin Wang <baolin.wang@linaro.org> - 2017-02-20 03:30 +0100
    Re: [PATCH] usb: dwc3: ep0: Fix the possible missed request for  handling delay STATUS phase Baolin Wang <baolin.wang@linaro.org> - 2017-02-21 10:20 +0100
      Re: [PATCH] usb: dwc3: ep0: Fix the possible missed request for  handling delay STATUS phase Alan Stern <stern@rowland.harvard.edu> - 2017-02-27 23:20 +0100
        Re: [PATCH] usb: dwc3: ep0: Fix the possible missed request for handling delay STATUS phase Felipe Balbi <balbi@kernel.org> - 2017-02-28 13:10 +0100
          Re: [PATCH] usb: dwc3: ep0: Fix the possible missed request for  handling delay STATUS phase Alan Stern <stern@rowland.harvard.edu> - 2017-02-28 20:00 +0100

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