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From:   Alex Deucher <alexdeucher@gmail.com>
Date:   Thu, 7 Jul 2022 14:22:20 -0400
Message-ID: <CADnq5_NpXcua54cSeSGaG2X_afcvoGswKgSb=Gysr5gpoT0AHw@mail.gmail.com>
Subject: Re: [PATCH] drm/amd/display: Fix unsigned expression compared with zero
To:     Zhongjun Tan <hbut_tan@163.com>,
        "Wentland, Harry" <Harry.Wentland@amd.com>
Cc:     "Leo (Sunpeng) Li" <sunpeng.li@amd.com>,
        "Siqueira, Rodrigo" <Rodrigo.Siqueira@amd.com>,
        "Deucher, Alexander" <alexander.deucher@amd.com>,
        Christian Koenig <christian.koenig@amd.com>,
        xinhui pan <Xinhui.Pan@amd.com>,
        Dave Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>,
        cai.huoqing@linux.dev, Zhongjun Tan <tanzhongjun@coolpad.com>,
        Maling list - DRI developers 
        <dri-devel@lists.freedesktop.org>,
        amd-gfx list <amd-gfx@lists.freedesktop.org>,
        LKML <linux-kernel@vger.kernel.org>
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On Wed, Jul 6, 2022 at 3:41 AM Zhongjun Tan <hbut_tan@163.com> wrote:
>
> From: Zhongjun Tan <tanzhongjun@coolpad.com>
>
> Fix unsigned expression compared with zero
>
> Signed-off-by: Zhongjun Tan <tanzhongjun@coolpad.com>
> ---
>  .../gpu/drm/amd/display/dc/dml/dcn20/display_rq_dlg_calc_20.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/display/dc/dml/dcn20/display_rq_dlg_calc_20.c b/drivers/gpu/drm/amd/display/dc/dml/dcn20/display_rq_dlg_calc_20.c
> index 548cdef8a8ad..21e4af38b8c1 100644
> --- a/drivers/gpu/drm/amd/display/dc/dml/dcn20/display_rq_dlg_calc_20.c
> +++ b/drivers/gpu/drm/amd/display/dc/dml/dcn20/display_rq_dlg_calc_20.c
> @@ -244,8 +244,8 @@ static void handle_det_buf_split(struct display_mode_lib *mode_lib,
>         bool req128_c = false;
>         bool surf_linear = (pipe_src_param->sw_mode == dm_sw_linear);
>         bool surf_vert = (pipe_src_param->source_scan == dm_vert);
> -       unsigned int log2_swath_height_l = 0;
> -       unsigned int log2_swath_height_c = 0;
> +       int log2_swath_height_l = 0;
> +       int log2_swath_height_c = 0;

@Wentland, Harry Can you comment on the required range needed for
these integers?  Maybe it would be better to just drop the comparisons
with 0.

Alex

>         unsigned int detile_buf_size_in_bytes = mode_lib->ip.det_buffer_size_kbytes * 1024;
>
>         full_swath_bytes_packed_l = rq_param->misc.rq_l.full_swath_bytes;
> --
> 2.29.0
>