Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <20200429092207.4049268-1-arnd@arndb.de> <f9738a59-5c7d-57ad-0d56-6455d6938964@amd.com>
In-Reply-To: <f9738a59-5c7d-57ad-0d56-6455d6938964@amd.com>
From:   Arnd Bergmann <arnd@arndb.de>
Date:   Wed, 29 Apr 2020 22:16:10 +0200
Message-ID: <CAK8P3a3YCKtkt2pHQZGg8SQsbdA2Ai3ZhxCGKToD2KVRHQgnrw@mail.gmail.com>
Subject: Re: [PATCH] [v2] amdgpu: fix gcc-4.8 build warnings
To:     "Kazlauskas, Nicholas" <nicholas.kazlauskas@amd.com>
Cc:     Harry Wentland <harry.wentland@amd.com>,
        Leo Li <sunpeng.li@amd.com>,
        Alex Deucher <alexander.deucher@amd.com>,
        =?UTF-8?Q?Christian_K=C3=B6nig?= <christian.koenig@amd.com>,
        "David (ChunMing) Zhou" <David1.Zhou@amd.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>,
        Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>,
        amd-gfx list <amd-gfx@lists.freedesktop.org>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Wed, Apr 29, 2020 at 3:42 PM Kazlauskas, Nicholas
<nicholas.kazlauskas@amd.com> wrote:
>
> On 2020-04-29 5:20 a.m., Arnd Bergmann wrote:
> > Older compilers warn about initializers with incorrect curly
> > braces:
> >
> > drivers/gpu/drm/drm_dp_mst_topology.c: In function 'drm_dp_mst_dsc_aux_for_port':
> > drivers/gpu/drm/drm_dp_mst_topology.c:5497:9: error: missing braces around initializer [-Werror=missing-braces]
> >    struct drm_dp_desc desc = { 0 };
> >           ^
> >
> > Change all instances in the amd gpu driver to using the GNU empty
> > initializer extension.
>
> These should actually be memset - instead of GCC complaining, it'll be
> clang instead.

I'm not sure what you mean, clang certainly supports most GNU extensions,
and this one is used all over the kernel.

There is a good reason for using memset instead of ={}, e.g. when you want
to be sure that all padding fields get initialized before copying
stack variables
to user space, but I find it a little harder to read.

       Arnd