Re: request for ioctl range for private devices

[Stephen Hemminger <shemminger@osdl.org>]

On Fri, 15 Sep 2006 17:43:56 -0700
Jim Gibbons <jim@gibbons.com> wrote:

> I can see that I wasn't as clear as I should have been.  Thank you for 
> trying to figure it out anyway.
> 
> Please let me try again to explain.  We are using a driver interface to 
> our kernel level code.  Our kernel level code is a loadable module.  We 
> have no intention of modifying the kernel or of releasing our code.  We 
> accept the implied maintenance responsibility on this private, embedded 
> platform.

Then why should the main kernel developers do anything to help you
with your private effort?

> We will, however, use code from the public Linux sources.  We are 
> planning to use 2.6 at the moment, but we hope to update in the future.  
> We also expect that we will update our platform, possibly adding new, 
> publicly supported devices to it.


So it is by definition a derived work under GPL

> In this environment, we want to allow our daemons to communicate with 
> our kernel module via its driver interface.
> 
> With all this having been said, we would like to find a range of ioctls 
> to use for this communication.  We don't want to reserve a range for 
> ourselves.  That would be silly, since this is such a private 
> situation.  We do think that such embedded use might be common, though, 
> and we would like to see a range of ioctls reserved for private and 
> experimental uses like ours.
> 
> I hope that such an ioctl range might be reserved, so that we can avoid 
> conflict with other public devices in the future.
> 
> Thanks for your help.
> 
> Miguel Ojeda wrote:
> > On 9/16/06, Jim Gibbons <jim@gibbons.com> wrote:
> >>
> >> I would like to use an ioctl range that would be safe, now and in the
> >> future.  Given that we won't be putting this driver on any general
> >> computing platforms, it seems inappropriate to reserve an ioctl range
> >> for this device.
> >>
> >
> > I'm trying to get a patch accepted, and I just modified the file to
> > appear in the ioctl-number list, so if they apply the patch, the magic
> > number will be automatically reserved.
> >
> > I think it's the right approach. Anyway, you should write and send the
> > device driver first, for review, because some people disagree with
> > your ioctl use, and maybe they can ask you for use another way to
> > communicate special commands to your device.
> >
> > If you are not going to submit the driver code ever, I think it will
> > be much more difficult to get a ioctl just for your private use. If
> > I'm right, you will have to keep your patch update on your own, as it
> > doesn't belong to linux at all.
> >
> >      Miguel Ojeda
> 
> -- 
> Jim Gibbons
> 	jim@gibbons.com
> Gibbons and Associates, Inc.
> 	TEL: (408) 984-1441
> 900 Lafayette, Suite 704, Santa Clara, CA
> 	FAX: (408) 247-6395
> 
> 
> 
> 
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