From: Michal Nazarewicz <mina86@mina86.com>
To: Robert Baldyga <r.baldyga@samsung.com>, balbi@ti.com
Cc: gregkh@linuxfoundation.org, linux-usb@vger.kernel.org,
        linux-kernel@vger.kernel.org, m.szyprowski@samsung.com,
        andrzej.p@samsung.com
Subject: Re: [PATCH v2 2/3] usb: gadget: f_fs: add ioctl returning ep descriptor
In-Reply-To: <53D5E958.40100@samsung.com>
Organization: http://mina86.com/
References: <1406295363-26998-1-git-send-email-r.baldyga@samsung.com> <1406295363-26998-3-git-send-email-r.baldyga@samsung.com> <xa1twqb1ttgq.fsf@mina86.com> <53D5E958.40100@samsung.com>
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Date: Mon, 28 Jul 2014 12:24:21 +0200
Message-ID: <xa1tha21rdbe.fsf@mina86.com>
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Sender: linux-kernel-owner@vger.kernel.org

>> On Fri, Jul 25 2014, Robert Baldyga wrote:
>>> This patch introduces ioctl named FUNCTIONFS_ENDPOINT_DESC, which
>>> returns endpoint descriptor to userspace. It works only if function
>>> is active.

> On 07/25/2014 04:15 PM, Michal Nazarewicz wrote:
>> I would argue that user space should never need to know the real
>> descriptor.  Is this ioctl needed for anything in particular?

On Mon, Jul 28 2014, Robert Baldyga <r.baldyga@samsung.com> wrote:
> It's needed, at least, to inform user space about maximum possible
> wMaxPacketSize value for the endpoint, which is returned by autoconfig
> through the endpoint descriptor when value set by user is zero.
>
> Descriptor returned form this ioctl is mostly the same as descriptor
> created by user. I guess you meant that real descriptor is this one,
> which contains real endpoint address, because it's probably only datum
> in real descriptor which should be never known by user space.
>
> This ioctl would be also useful in case, when FunctionFS daemon obtains
> endpoint descriptors from another daemon, and do not have access to
> original descriptor structures given do FunctionFS.

All right, I think I can go with that.

>>> Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>

-- 
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.o. | Liege of Serenely Enlightened Majesty of      o' \,=./ `o
..o | Computer Science,  Michał “mina86” Nazarewicz    (o o)
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