linux-kernel - Re: [PATCH 1/2] usb: gadget: composite: Allow function drivers to defer setup responses

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Date:	Thu, 21 Apr 2011 16:27:14 +0300
From:	Roger Quadros <roger.quadros@...ia.com>
To:	ext Alan Stern <stern@...land.harvard.edu>
CC:	<gregkh@...e.de>, <mina86@...a86.com>, <m-sonasath@...com>,
	USB list <linux-usb@...r.kernel.org>,
	Kernel development list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] usb: gadget: composite: Allow function drivers to
 defer setup responses

On 04/19/2011 05:14 PM, ext Alan Stern wrote:
> On Tue, 19 Apr 2011, Roger Quadros wrote:
>
>> +/**
>> + * usb_composite_setup_continue() - Continue the delayed setup transfer
>
> You're should say "control transfer", not "setup transfer".  Control
> transfers consist of a setup stage, an optional data stage, and a
> status stage.  The setup stage has already ended by the time the
> function's setup handler is called.

Yes I will re-word the things and re-send the patches.

>
>> + * @cdev: the composite device who's setup transfer was delayed
>> + *
>> + * This function must be called by the USB function driver to continue
>> + * with the setup transfer's data/status phase in case it had requested to
>
> Data and Status are stages, not phases.  See section 8.5.3 of the
> USB-2.0 spec.
>
> You made these mistakes in a few different places throughout the patch.
>
>> + * delay the status phase. A USB function's setup handler (e.g. set_alt())
>> + * can request the composite framework to delay the setup request's status phase
>> + * by returning USB_GADGET_DELAYED_STATUS.
>> + */
>> +void usb_composite_setup_continue(struct usb_composite_dev *cdev)
>> +{
>> +	int			value;
>> +	struct usb_request	*req = cdev->req;
>> +	unsigned long		flags;
>> +
>> +	DBG(cdev, "%s\n", __func__);
>> +	spin_lock_irqsave(&cdev->lock, flags);
>> +
>> +	if (cdev->delayed_status == 0) {
>> +		WARN(cdev, "%s: Unexpected call\n", __func__);
>> +
>> +	} else if (--cdev->delayed_status == 0) {
>> +		DBG(cdev, "%s: Completing delayed status\n", __func__);
>> +		req->length = 0;
>> +		req->zero = 1;
>
> There's no reason to set this flag.  It has no effect when req->length
> is 0.
>
OK.

Thanks for review.

-- 
regards,
-roger
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