Re: [PATCH] usb: gadget: function: acm: return zlp for OUT setup

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On Wed, Oct 14, 2015 at 11:18 PM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
> On Wed, 14 Oct 2015, Jassi Brar wrote:
>
>> BTW, should the gadget stack ever queue a Non-ZLP as reply to some
>> setup request that has USB_DIR_IN not set?
>
> Yes.  If USB_DIR_IN is not set then the control transfer is OUT, so the
> gadget needs to queue a request to receive some data from the host.
> That request will obviously need to be a non-ZLP.
>
By 'reply' I meant after reading out and parsing the
setup(control-out) request. I am sure we need to send a ZLP.

> Could this cause the problem you're seeing?  The host tries to send
> more data than the gadget is ready to receive?  (Although then the
> error code on the gadget side should be -75, not -71.)
>
Thanks, but as you said my problem is not that (I get protocol error
-71).  My problem is my udc driver actually tries to send a 7 byte
response to a control-out command.
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