All of lore.kernel.org
 help / color / mirror / Atom feed
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Chris Dickens <christopher.a.dickens@gmail.com>
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: Fri, 3 Jul 2020 08:00:13 +0200	[thread overview]
Message-ID: <20200703060013.GA6188@kroah.com> (raw)
In-Reply-To: <CAL-1MmUi6OajEYNuP+OOEeekesZJjAGP-8VDSjGydXAMEFHhMA@mail.gmail.com>

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

  reply	other threads:[~2020-07-03  6:00 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 [this message]
2020-07-03  6:47   ` Chris Dickens
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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200703060013.GA6188@kroah.com \
    --to=gregkh@linuxfoundation.org \
    --cc=andrzej.p@samsung.com \
    --cc=balbi@kernel.org \
    --cc=christopher.a.dickens@gmail.com \
    --cc=linux-usb@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.