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Date: Wed, 19 Aug 2009 11:11:02 -0700
From: Greg KH <greg@kroah.com>
To: "Rick L. Vinyard, Jr." <rvinyard@cs.nmsu.edu>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>, Linux USB <linux-usb@vger.kernel.org>,
       LKML <linux-kernel@vger.kernel.org>
Subject: Re: Purpose of parameter in sysfs binary read
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On Wed, Aug 19, 2009 at 11:41:28AM -0600, Rick L. Vinyard, Jr. wrote:
> Alan Cox wrote:
> > On Tue, 18 Aug 2009 09:41:56 -0600
> > "Rick L. Vinyard, Jr." <rvinyard@cs.nmsu.edu> wrote:
> >
> >> Greg KH wrote:
> >> > On Tue, Aug 18, 2009 at 08:55:29AM -0600, Rick L. Vinyard, Jr. wrote:
> >> > What are you using the binary sysfs attribute for?  It should ONLY be
> >> > used as a pass-through to and from hardware, with no interpretation by
> >> > the kernel at all.
> >>
> >> It's for the Logitech G13's game panel image (a simple binary bitmap of
> >> the pixels).
> >>
> >> It doesn't do any interpretation... just a few checks on the magic
> >> number
> >> and size.
> >
> > If its a bitmap image why not register the device as a framebuffer ?
> >
> 
> Would that preclude it also being registered as a HID? The primary purpose
> of the device is to function as a keypad input.

Is the framebuffer a different USB interface?  Or are they all
controlled through the same one?

thanks,

greg k-h