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Date:   Wed, 21 Dec 2022 21:05:34 +0530
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Subject: Re: [PATCH 04/10] drm/print: Fix support for NULL as first argument
 of drm_dbg_*
To:     Jani Nikula <jani.nikula@linux.intel.com>
Cc:     linux-kernel <linux-kernel@vger.kernel.org>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <mripard@kernel.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>
References: <cover.1671566741.git.code@siddh.me>
 <3ebf0d61ad5e82875a4493108602e62429306b14.1671566741.git.code@siddh.me>
 <87edst2ix8.fsf@intel.com>
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From:   Siddh Raman Pant <code@siddh.me>
Message-ID: <21113999-99c2-0273-a6fe-8374ee910297@siddh.me>
In-Reply-To: <87edst2ix8.fsf@intel.com>
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On Wed, Dec 21 2022 at 15:11:07 +0530, Jani Nikula wrote:
> On Wed, 21 Dec 2022, Siddh Raman Pant <code@siddh.me> wrote:
>> Comments say macros DRM_DEBUG_* are deprecated in favor of
>> drm_dbg_*(NULL, ...), but they have broken support for it,
>> as the macro will result in `(NULL) ? (NULL)->dev : NULL`.
>=20
> What's wrong with that?

NULL is not a struct, so the syntax is incorrect.

Note that this isn't about a dev pointer whose value is
NULL, the first argument is NULL directly. So "NULL" is
directly substituted as is. If it was a dev pointer, then
the definition of struct allowed for no error, but here
gcc will generate the following error:

error: request for member =E2=80=98dev=E2=80=99 in something not a structur=
e or union=20

Hence, there is a need to fix them.

Thanks,
Siddh