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Subject: Re: [RFC PATCH 0/3] Add device tree build information
From: Frank Rowand <frowand.list@gmail.com>
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Date: Mon, 20 Jan 2020 21:39:28 -0600
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To: Steve McIntyre <steve.mcintyre@linaro.org>
Cc: Alexandre Torgue <alexandre.torgue@st.com>, robh+dt@kernel.org, Masahiro Yamada <masahiroy@kernel.org>, Michal Marek <michal.lkml@markovi.net>, david@gibson.dropbear.id.au, sjg@chromium.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, devicetree-compiler@vger.kernel.org

On 1/20/20 9:20 PM, Frank Rowand wrote:
> On 1/20/20 12:28 PM, Steve McIntyre wrote:
>> Hi Frank!
>>
>> Thanks for the link back to the previous discussion, it's very
>> helpful.
>>
>> On Mon, Jan 20, 2020 at 10:14:22AM -0600, Frank Rowand wrote:
>>> On 1/20/20 4:56 AM, Alexandre Torgue wrote:
>>
>> ...
>>
>>>> and the date). There are no "dtb versions", and "absolute/relative"
>>>> path which created concerns. One remaining concern is "reproducible
>>>
>>> Here is an example of the info from one of my builds:
>>>
>>>   From Linux 5.5.0-rc2-dirty by frowand the Mon Jan 20 09:50:58 CST 2020.
>>>
>>> The information 'Linux 5.5.0-rc2-dirty' is precisely what was most objected
>>> to in my proposal.
>>
>> ACK. :-( I'm surprised to see so much push-back on what looks like a
>> simple piece of information here.
> 
> Me too.
> 
> 
>>
>> I've had users *specifically* asking for this kind of identification
>> so that they can verify the version of the DTB they're using at
>> runtime. Right now it can be a guessing game, which does not help
>> people trying to debug problems.
>>
>> Cheers,
>>
> 
> If the information was reported as debug information via pr_debug(),
> would that work for your use case?  Or would the users' kernels
> not have debug enabled in the configuration?

And even pr_debug() might not be sufficient since the property
value is available via /proc/device-tree if the proc file
system is enabled.