From: Felipe Balbi <balbi@ti.com>
To: Alan Stern <stern@rowland.harvard.edu>,
Jassi Brar <jassisinghbrar@gmail.com>
Cc: Jaswinder Singh <jaswinder.singh@linaro.org>,
"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
<stable@vger.kernel.org>
Subject: Re: [PATCH] usb: gadget: function: acm: return zlp for OUT setup
Date: Wed, 14 Oct 2015 13:32:09 -0500 [thread overview]
Message-ID: <87y4f59u8m.fsf@saruman.tx.rr.com> (raw)
In-Reply-To: <Pine.LNX.4.44L0.1510141341320.1644-100000@iolanthe.rowland.org>
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Hi,
Alan Stern <stern@rowland.harvard.edu> writes:
> 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. In fact, it's hard
> to think of a situation where a gadget would ever want to submit a
> zero-length OUT request. Isn't the UDC driver supposed to handle the
> status stage of a control-IN transfer automatically?
yes and no. :-) If USB_GADGET_DELAYED_STATUS is returned, we need to
wait for the gadget driver to queue a request.
--
balbi
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next prev parent reply other threads:[~2015-10-14 18:32 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-14 14:56 [PATCH] usb: gadget: function: acm: return zlp for OUT setup jaswinder.singh
2015-10-14 15:12 ` Felipe Balbi
2015-10-14 15:33 ` Jassi Brar
2015-10-14 15:48 ` Felipe Balbi
2015-10-14 16:43 ` Jassi Brar
2015-10-14 17:10 ` Felipe Balbi
2015-10-15 3:27 ` Jassi Brar
2015-10-15 19:18 ` Felipe Balbi
2015-10-14 17:48 ` Alan Stern
2015-10-14 18:32 ` Felipe Balbi [this message]
2015-10-14 19:32 ` Alan Stern
2015-10-15 3:38 ` Jassi Brar
2015-10-15 14:29 ` Alan Stern
2015-10-15 14:51 ` Jassi Brar
2015-10-15 16:55 ` Alan Stern
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