From: Chris Dickens <christopher.a.dickens@gmail.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb <linux-usb@vger.kernel.org>,
Felipe Balbi <balbi@kernel.org>,
andrzej.p@samsung.com
Subject: Re: gadget: Why do Microsoft OS descriptors need their own USB request?
Date: Thu, 2 Jul 2020 23:47:09 -0700 [thread overview]
Message-ID: <CAL-1MmX7xKjYUUAgSGfJ7roi6W3ucD+oyQT4vmxAaDtJpjU07Q@mail.gmail.com> (raw)
In-Reply-To: <20200703060013.GA6188@kroah.com>
Well, the history shows it was there from the very beginning, so it is
unclear (at least to me) why it was needed.
Chris
On Thu, Jul 2, 2020 at 11:00 PM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> On Thu, Jul 02, 2020 at 05:11:11PM -0700, Chris Dickens wrote:
> > Hi,
> >
> > I've never understood it, so I figure I might as well just ask. Why
> > does the Microsoft OS descriptors support require the allocation of a
> > separate USB request for the composite gadget device? Both the
> > default control request buffer and the "special" OS descriptors buffer
> > are the same size (4KB) and use the same completion handler. As far
> > as I can tell there is nothing distinct between them. There's only
> > ever one outstanding USB request queued to ep0, so can the dedicated
> > USB request be removed and just share the default one? I'm happy to
> > provide a patch, unless of course I've missed something.
>
> Try it and see, I think it was needed for some reason, but look at git
> history to be sure.
>
> thanks,
>
> greg k-h
next prev parent reply other threads:[~2020-07-03 6:47 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-03 0:11 gadget: Why do Microsoft OS descriptors need their own USB request? Chris Dickens
2020-07-03 6:00 ` Greg Kroah-Hartman
2020-07-03 6:47 ` Chris Dickens [this message]
2020-07-03 6:57 ` Greg Kroah-Hartman
2020-07-03 7:03 ` Chris Dickens
2020-07-03 7:24 ` Greg Kroah-Hartman
2020-07-03 8:35 ` [PATCH] usb: gadget: composite: Remove dedicated OS Feature Descriptors request Chris Dickens
2020-07-03 8:57 ` Greg Kroah-Hartman
2020-07-25 6:12 ` Felipe Balbi
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