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

[Felipe Balbi]

Hi,

Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> 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