Message-ID: <54D0D46E.2040907@hurleysoftware.com>
Date: Tue, 03 Feb 2015 09:00:14 -0500
From: Peter Hurley <peter@hurleysoftware.com>
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To: Stefan Richter <stefanr@s5r6.in-berlin.de>
CC: Clemens Ladisch <clemens@ladisch.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        devel@driverdev.osuosl.org, linux1394-devel@lists.sourceforge.net,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] staging/fwserial: use correct vendor/version IDs
References: <54C940E0.5090906@ladisch.de>	<54C9418F.1050600@ladisch.de>	<54CFF560.300@hurleysoftware.com> <20150203094425.2def7f79@kant>
In-Reply-To: <20150203094425.2def7f79@kant>
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On 02/03/2015 03:44 AM, Stefan Richter wrote:
> On Feb 02 Peter Hurley wrote:
>> On 01/28/2015 03:07 PM, Clemens Ladisch wrote:
>>> The driver was using the vendor ID 0xd00d1e from the FireWire core.
>>> However, this ID was not registered, and invalid.
>>>
>>> Instead, use the vendor/version IDs that now are officially assigned to
>>> firewire-serial:
>>> https://ieee1394.wiki.kernel.org/index.php/IEEE_OUI_Assignments
>>
>> That's great that we have official OUIs now, but I have to NACK this
>> patch as is.
>>
>> The problem is a host with the old OUIs will not recognize a remote
>> unit with the new OUIs, and vice versa.
>>
>> Even though the new ids could be added to the unit driver's id_table,
>> (which would let hosts with the new OUI connect to either OUI remote),
>> it wouldn't let 3.19- hosts connect to 3.20+ hosts.
> 
> Actually there are no 3.19- hosts that speak fwserial; there are only
> staging hosts that do so.  So, with this patch added, certain staging
> hosts would become unable to talk with certain other staging hosts (and
> with future Linux hosts, once fwserial gets merged upstream).

The breakage seems gratuitous especially considering the existing OUI
has been in use for a decade.

> Both fwserial-the-implementation and fwserial-the-protocol are your own,
> and as yet unmerged.

I've been waiting for you to work through the patch backlog from Feb and
Mar of last year before sending you more patches to merge fwserial.

>  (In addition, there does not yet exist a second
> implementation, AFAIK.)  So I'd say there is still opportunity to improve
> the protocol even in incompatible ways if justified.  Switching to
> valid identifiers may very well be such a justifiable change.

I would appreciate you sharing any suggestions for improving the protocol.

While I concede the protocol is not perfect, I'm struggling to see how
changing the OUI improves it.

Regards,
Peter Hurley


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