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From:   Chun-Kuang Hu <chunkuang.hu@kernel.org>
Date:   Tue, 12 Jan 2021 08:20:02 +0800
Message-ID: <CAAOTY__+DzbaAi=YUsx0_Sbq9rYzddCgiBvDMQyHgKSOiRvpjA@mail.gmail.com>
Subject: Re: [PATCH v3, 08/15] drm/mediatek: check if fb is null
To:     Yongqiang Niu <yongqiang.niu@mediatek.com>
Cc:     CK Hu <ck.hu@mediatek.com>, Philipp Zabel <p.zabel@pengutronix.de>,
        Rob Herring <robh+dt@kernel.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Mark Rutland <mark.rutland@arm.com>,
        DTML <devicetree@vger.kernel.org>,
        David Airlie <airlied@linux.ie>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        DRI Development <dri-devel@lists.freedesktop.org>,
        Project_Global_Chrome_Upstream_Group@mediatek.com,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@lists.infradead.org>,
        Daniel Vetter <daniel@ffwll.ch>,
        Hsin-Yi Wang <hsinyi@chromium.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>
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Hi, Yongqiang:

Yongqiang Niu <yongqiang.niu@mediatek.com> =E6=96=BC 2021=E5=B9=B41=E6=9C=
=8811=E6=97=A5 =E9=80=B1=E4=B8=80 =E4=B8=8B=E5=8D=883:48=E5=AF=AB=E9=81=93=
=EF=BC=9A
>
> It's possible that state->base.fb is null. Add a check before access its
> format.

Applied to mediatek-drm-next [1], thanks.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux.git/=
log/?h=3Dmediatek-drm-next

Regards,
Chun-Kuang.

>
> Fixes: b6b1bb980ec4 ( drm/mediatek: Turn off Alpha bit when plane format =
has no alpha)
> Signed-off-by: Yongqiang Niu <yongqiang.niu@mediatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_disp_ovl.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c b/drivers/gpu/drm/me=
diatek/mtk_disp_ovl.c
> index 4934bee..8e7f494 100644
> --- a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
> +++ b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
> @@ -279,7 +279,7 @@ static void mtk_ovl_layer_config(struct mtk_ddp_comp =
*comp, unsigned int idx,
>         }
>
>         con =3D ovl_fmt_convert(ovl, fmt);
> -       if (state->base.fb->format->has_alpha)
> +       if (state->base.fb && state->base.fb->format->has_alpha)
>                 con |=3D OVL_CON_AEN | OVL_CON_ALPHA;
>
>         if (pending->rotation & DRM_MODE_REFLECT_Y) {
> --
> 1.8.1.1.dirty
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