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From:   Alex Deucher <alexdeucher@gmail.com>
Date:   Mon, 27 Mar 2023 19:53:36 -0400
Message-ID: <CADnq5_OG8pDyYruc4VCpd_eG8MxZUDf+nPr4zTy+u-7-a5L6uw@mail.gmail.com>
Subject: Re: [PATCH 12/12] drm/amd/display: Remove two unused variables
 'result_write_min_hblank' and 'hblank_size'
To:     Caio Novais <caionovais@usp.br>
Cc:     amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org, Felipe Clark <felipe.clark@amd.com>,
        Wenjing Liu <wenjing.liu@amd.com>,
        =?UTF-8?B?TWHDrXJhIENhbmFs?= <mairacanal@riseup.net>,
        Mario Limonciello <mario.limonciello@amd.com>,
        Jun Lei <Jun.Lei@amd.com>, David Airlie <airlied@gmail.com>,
        Charlene Liu <Charlene.Liu@amd.com>,
        Gabe Teeger <gabe.teeger@amd.com>,
        Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>,
        Taimur Hassan <Syed.Hassan@amd.com>,
        Aurabindo Pillai <aurabindo.pillai@amd.com>,
        Alvin Lee <alvin.lee2@amd.com>,
        George Shen <George.Shen@amd.com>,
        Hamza Mahfooz <hamza.mahfooz@amd.com>,
        Chaitanya Dhere <chaitanya.dhere@amd.com>,
        Harry Wentland <harry.wentland@amd.com>,
        Alan Liu <HaoPing.Liu@amd.com>,
        Mukul Joshi <mukul.joshi@amd.com>,
        =?UTF-8?Q?Andr=C3=A9_Almeida?= <andrealmeid@igalia.com>,
        Jingwen Zhu <Jingwen.Zhu@amd.com>,
        Guo Zhengkui <guozhengkui@vivo.com>,
        Leo Li <sunpeng.li@amd.com>, Melissa Wen <mwen@igalia.com>,
        Le Ma <le.ma@amd.com>,
        Jiapeng Chong <jiapeng.chong@linux.alibaba.com>,
        Martin Leung <Martin.Leung@amd.com>,
        Ryan Lin <tsung-hua.lin@amd.com>,
        Brian Chang <Brian.Chang@amd.com>,
        Sung Joon Kim <sungjoon.kim@amd.com>,
        Yifan Zhang <yifan1.zhang@amd.com>,
        Jack Xiao <Jack.Xiao@amd.com>,
        Dillon Varone <Dillon.Varone@amd.com>,
        Tom Chung <chiahsuan.chung@amd.com>,
        Wesley Chalmers <Wesley.Chalmers@amd.com>,
        Qingqing Zhuo <qingqing.zhuo@amd.com>,
        "Pan, Xinhui" <Xinhui.Pan@amd.com>, Zhan Liu <zhan.liu@amd.com>,
        Roman Li <Roman.Li@amd.com>,
        =?UTF-8?Q?Christian_K=C3=B6nig?= <christian.koenig@amd.com>,
        Daniel Vetter <daniel@ffwll.ch>, Wayne Lin <wayne.lin@amd.com>,
        Alex Deucher <alexander.deucher@amd.com>,
        Ethan Wellenreiter <Ethan.Wellenreiter@amd.com>,
        Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>,
        Joshua Ashton <joshua@froggi.es>,
        Hawking Zhang <Hawking.Zhang@amd.com>
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On Mon, Mar 27, 2023 at 7:36=E2=80=AFPM Caio Novais <caionovais@usp.br> wro=
te:
>
> Compiling AMD GPU drivers displays a warning:
>
> drivers/gpu/drm/amd/amdgpu/../display/dc/link/protocols/link_dp_capabilit=
y.c: In function =E2=80=98dpcd_set_source_specific_data=E2=80=99:
> drivers/gpu/drm/amd/amdgpu/../display/dc/link/protocols/link_dp_capabilit=
y.c:1290:32: warning: variable =E2=80=98result_write_min_hblank=E2=80=99 se=
t but not used [-Wunused-but-set-variable]
>
> Get rid of it by removing the variable 'result_write_min_hblank' and 'hbl=
ank_size'.
>
> Signed-off-by: Caio Novais <caionovais@usp.br>
> ---
>  .../drm/amd/display/dc/link/protocols/link_dp_capability.c | 7 -------
>  1 file changed, 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capabi=
lity.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
> index d4370856f164..7392fcf17653 100644
> --- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
> +++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
> @@ -1287,7 +1287,6 @@ void dc_link_overwrite_extended_receiver_cap(
>  void dpcd_set_source_specific_data(struct dc_link *link)
>  {
>         if (!link->dc->vendor_signature.is_valid) {
> -               enum dc_status result_write_min_hblank =3D DC_NOT_SUPPORT=
ED;
>                 struct dpcd_amd_signature amd_signature =3D {0};
>                 struct dpcd_amd_device_id amd_device_id =3D {0};
>
> @@ -1324,16 +1323,10 @@ void dpcd_set_source_specific_data(struct dc_link=
 *link)
>                 if (link->ctx->dce_version >=3D DCN_VERSION_2_0 &&
>                         link->dc->caps.min_horizontal_blanking_period !=
=3D 0) {
>
> -                       uint8_t hblank_size =3D (uint8_t)link->dc->caps.m=
in_horizontal_blanking_period;
> -
> -                       result_write_min_hblank =3D core_link_write_dpcd(=
link,
> -                               DP_SOURCE_MINIMUM_HBLANK_SUPPORTED, (uint=
8_t *)(&hblank_size),
> -                               sizeof(hblank_size));

This writes to the monitor.  We shouldn't remove this.

>                 }
>                 DC_TRACE_LEVEL_MESSAGE(DAL_TRACE_LEVEL_INFORMATION,
>                                                         WPP_BIT_FLAG_DC_D=
ETECTION_DP_CAPS,
>                                                         "result=3D%u link=
_index=3D%u enum dce_version=3D%d DPCD=3D0x%04X min_hblank=3D%u branch_dev_=
id=3D0x%x branch_dev_name=3D'%c%c%c%c%c%c'",
> -                                                       result_write_min_=
hblank,

You are dropping information from the debug logging.  Maybe it would
be better to just flag this as maybe unused.  Also, I'd suggest
rebasing on the latest amdgpu -next branch, as I think a lot of these
were already fixed last week or the week before.

Alex

>                                                         link->link_index,
>                                                         link->ctx->dce_ve=
rsion,
>                                                         DP_SOURCE_MINIMUM=
_HBLANK_SUPPORTED,
> --
> 2.40.0
>