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Subject: Re: [PATCH] arm: exynos_config: Restore debugfs support
To:     Steven Rostedt <rostedt@goodmis.org>
Cc:     Kusanagi Kouichi <slash@ac.auone-net.jp>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org,
        Krzysztof Kozlowski <krzk@kernel.org>
From:   Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Message-ID: <5fdca7d0-c130-457a-2ce2-74f645b60f8d@samsung.com>
Date:   Mon, 25 Nov 2019 16:31:07 +0100
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On 11/25/19 3:39 PM, Steven Rostedt wrote:
> On Mon, 25 Nov 2019 15:30:39 +0100
> Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> wrote:
> 
>> It seems that commit 0e4a459f56c3 ("tracing: Remove unnecessary DEBUG_FS
>> dependency") disabled DEBUG_FS also in some other ARM defconfigs.
>>
>> For some of them it may be a correct change but a preferred way to
>> introduce such changes would be to:
>>
>> - add explicit CONFIG_DEBUG_FS=y instances to all affected defconfigs
>>   while removing DEBUG_FS selection from TRACING config item
>>
> 
> I strongly disagree. It was wrong to assume DEBUG_FS is attached to
> TRACING. If someone wanted DEBUG_FS in their def config, they should
> have added it specifically. The addition of DEBUG_FS to defconfigs no

There is a theory and a practice.

In theory you are are correct. ;-)

In practice people don't manually edit configuration files nowadays.

They do 'make menuconfig' and enable what they need and disable what
they do not need.  Then they do 'make savedefconfig' and copy resulting
"stripped" defconfig file as their new platform defconfig. As a result
defconfigs rely on many default settings (also they explicitly disable
only items that are enabled by default but you don't want them).

> way belongs to the patch that removed DEBUG_FS from TRACING.
> 
> -- Steve
> 
> 
>> - let platform maintainers disable DEBUG_FS manually in corresponding
>>   defconfigs later if desirable

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics