linux-kernel - Re: [PATCH] drm/amd/display: remove variable backlight

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Date:   Tue, 10 Aug 2021 10:13:24 -0400
From:   Alex Deucher <alexdeucher@...il.com>
To:     zhaoxiao <zhaoxiao@...ontech.com>
Cc:     Dave Airlie <airlied@...ux.ie>, Daniel Vetter <daniel@...ll.ch>,
        "Wentland, Harry" <harry.wentland@....com>,
        "Leo (Sunpeng) Li" <sunpeng.li@....com>,
        "Deucher, Alexander" <alexander.deucher@....com>,
        Christian Koenig <christian.koenig@....com>,
        xinhui pan <Xinhui.Pan@....com>,
        Nirmoy Das <nirmoy.das@....com>,
        amd-gfx list <amd-gfx@...ts.freedesktop.org>,
        Maling list - DRI developers 
        <dri-devel@...ts.freedesktop.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] drm/amd/display: remove variable backlight

On Mon, Aug 9, 2021 at 9:24 PM zhaoxiao <zhaoxiao@...ontech.com> wrote:
>
> The variable backlight is being initialized with a value that
> is never read, it is being re-assigned immediately afterwards.

I don't think this comment really matches the code.  I think you can drop it.

Alex

> Clean up the code by removing the need for variable backlight.
>
> Signed-off-by: zhaoxiao <zhaoxiao@...ontech.com>
> ---
>  drivers/gpu/drm/amd/display/dc/dce/dce_abm.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_abm.c b/drivers/gpu/drm/amd/display/dc/dce/dce_abm.c
> index 874b132fe1d7..0808433185f8 100644
> --- a/drivers/gpu/drm/amd/display/dc/dce/dce_abm.c
> +++ b/drivers/gpu/drm/amd/display/dc/dce/dce_abm.c
> @@ -177,23 +177,21 @@ static void dce_abm_init(struct abm *abm, uint32_t backlight)
>  static unsigned int dce_abm_get_current_backlight(struct abm *abm)
>  {
>         struct dce_abm *abm_dce = TO_DCE_ABM(abm);
> -       unsigned int backlight = REG_READ(BL1_PWM_CURRENT_ABM_LEVEL);
>
>         /* return backlight in hardware format which is unsigned 17 bits, with
>          * 1 bit integer and 16 bit fractional
>          */
> -       return backlight;
> +       return REG_READ(BL1_PWM_CURRENT_ABM_LEVEL);
>  }
>
>  static unsigned int dce_abm_get_target_backlight(struct abm *abm)
>  {
>         struct dce_abm *abm_dce = TO_DCE_ABM(abm);
> -       unsigned int backlight = REG_READ(BL1_PWM_TARGET_ABM_LEVEL);
>
>         /* return backlight in hardware format which is unsigned 17 bits, with
>          * 1 bit integer and 16 bit fractional
>          */
> -       return backlight;
> +       return REG_READ(BL1_PWM_TARGET_ABM_LEVEL);
>  }
>
>  static bool dce_abm_set_level(struct abm *abm, uint32_t level)
> --
> 2.20.1
>
>
>