Message-ID: <450B48CC.6060604@gibbons.com>
Date: Fri, 15 Sep 2006 17:43:56 -0700
From: Jim Gibbons <jim@gibbons.com>
Reply-To: jim@gibbons.com
Organization: Gibbons and Associates, Inc.
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To: Miguel Ojeda <maxextreme@gmail.com>
CC: linux-kernel@vger.kernel.org
Subject: Re: request for ioctl range for private devices
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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.

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.

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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