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Subject: Re: [RFC PATCH 0/3] Add device tree build information
From:   Frank Rowand <frowand.list@gmail.com>
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
References: <20200113181625.3130-1-alexandre.torgue@st.com>
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 <233e0a5f-d38f-908c-5ca7-66ee87d0fcae@st.com>
 <7cfd0bc0-13fd-98ea-9bfd-6cfbbfd77b6d@gmail.com>
 <220e3aea-b273-417a-69c9-059236c888af@st.com>
 <a1233cd8-e73a-82d7-74bf-69109d1a0a07@gmail.com>
 <20200120182837.GO3697@linaro.org>
 <f09ce50c-6721-c9d3-4f27-3f98a2d0b183@gmail.com>
Message-ID: <e8cdbcaa-800b-18db-11ec-3d8df9da68b5@gmail.com>
Date:   Mon, 20 Jan 2020 21:39:28 -0600
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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.