linux-kernel - Re: [PATCH] drm/amdgpu: Unnecessary code in gfx_v7

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Message-ID: <CADnq5_PXDyOXX2p4FswWWyY6sw8nXmajhUzx-=ke+6jiZn3ZPA@mail.gmail.com>
Date:   Wed, 6 Apr 2022 09:19:49 -0400
From:   Alex Deucher <alexdeucher@...il.com>
To:     Grigory Vasilyev <h0tc0d3@...il.com>
Cc:     Rodrigo Siqueira <Rodrigo.Siqueira@....com>,
        Melissa Wen <mwen@...lia.com>,
        Bhaskar Chowdhury <unixbhaskar@...il.com>,
        Joseph Greathouse <Joseph.Greathouse@....com>,
        Guchun Chen <guchun.chen@....com>,
        "Pan, Xinhui" <Xinhui.Pan@....com>,
        LKML <linux-kernel@...r.kernel.org>,
        amd-gfx list <amd-gfx@...ts.freedesktop.org>,
        David Airlie <airlied@...ux.ie>,
        Maling list - DRI developers 
        <dri-devel@...ts.freedesktop.org>,
        Alex Deucher <alexander.deucher@....com>,
        Evan Quan <evan.quan@....com>,
        Lee Jones <lee.jones@...aro.org>,
        Christian König <christian.koenig@....com>
Subject: Re: [PATCH] drm/amdgpu: Unnecessary code in gfx_v7_0.c

On Wed, Apr 6, 2022 at 4:00 AM Grigory Vasilyev <h0tc0d3@...il.com> wrote:
>
> The code is useless and doesn't change the value.
>
> (0 << GB_ADDR_CONFIG__ROW_SIZE__SHIFT) = 0
> gb_addr_config | 0 = gb_addr_config
>
> Perhaps there could be 1 instead of 0, but this does not correspond with
> the logic of the switch.

It doesn't do anything, but it helps the developer to understand how
the driver state maps to hardware state.

Alex

>
> Signed-off-by: Grigory Vasilyev <h0tc0d3@...il.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/gfx_v7_0.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v7_0.c b/drivers/gpu/drm/amd/amdgpu/gfx_v7_0.c
> index 1cb5db17d2b9..5ed84a6467ee 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gfx_v7_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gfx_v7_0.c
> @@ -4409,16 +4409,14 @@ static void gfx_v7_0_gpu_early_init(struct amdgpu_device *adev)
>         /* fix up row size */
>         gb_addr_config &= ~GB_ADDR_CONFIG__ROW_SIZE_MASK;
>         switch (adev->gfx.config.mem_row_size_in_kb) {
> -       case 1:
> -       default:
> -               gb_addr_config |= (0 << GB_ADDR_CONFIG__ROW_SIZE__SHIFT);
> -               break;
>         case 2:
>                 gb_addr_config |= (1 << GB_ADDR_CONFIG__ROW_SIZE__SHIFT);
>                 break;
>         case 4:
>                 gb_addr_config |= (2 << GB_ADDR_CONFIG__ROW_SIZE__SHIFT);
>                 break;
> +       default:
> +               break;
>         }
>         adev->gfx.config.gb_addr_config = gb_addr_config;
>  }
> --
> 2.35.1
>