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From:   Chun-Kuang Hu <chunkuang.hu@kernel.org>
Date:   Tue, 8 Sep 2020 06:56:36 +0800
Message-ID: <CAAOTY_-BQx0rozw0qoGj1bt4hO2rFmYvKrjQHbA-K04txUWW+w@mail.gmail.com>
Subject: Re: [PATCH] drm/mediatek: add missing put_device() call in mtk_ddp_comp_init()
To:     Yu Kuai <yukuai3@huawei.com>
Cc:     Chun-Kuang Hu <chunkuang.hu@kernel.org>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        yt.shen@mediatek.com, CK Hu <ck.hu@mediatek.com>,
        Bibby Hsieh <bibby.hsieh@mediatek.com>,
        Yongqiang Niu <yongqiang.niu@mediatek.com>,
        DRI Development <dri-devel@lists.freedesktop.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@lists.infradead.org>,
        linux-kernel <linux-kernel@vger.kernel.org>, yi.zhang@huawei.com
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Hi Yu Kuai:

Yu Kuai <yukuai3@huawei.com> =E6=96=BC 2020=E5=B9=B49=E6=9C=885=E6=97=A5 =
=E9=80=B1=E5=85=AD =E4=B8=8B=E5=8D=884:31=E5=AF=AB=E9=81=93=EF=BC=9A
>
> if of_find_device_by_node() succeed, mtk_ddp_comp_init() doesn't have
> a corresponding put_device(). Thus add put_device() to fix the exception
> handling for this function implementation.
>

This patch looks good to me, but I find another thing related to this.
mtk_ddp_comp_init() is called in a loop in mtk_drm_probe(), when this
component init fail, I think we should uninitialize previous
successive init component and put their device. Would you like to make
this patch more complete?

Regards,
Chun-Kuang.

> Fixes: d0afe37f5209 ("drm/mediatek: support CMDQ interface in ddp compone=
nt")
> Signed-off-by: Yu Kuai <yukuai3@huawei.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c b/drivers/gpu/dr=
m/mediatek/mtk_drm_ddp_comp.c
> index 57c88de9a329..526648885b97 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> @@ -496,6 +496,7 @@ int mtk_ddp_comp_init(struct device *dev, struct devi=
ce_node *node,
>  #if IS_REACHABLE(CONFIG_MTK_CMDQ)
>         if (of_address_to_resource(node, 0, &res) !=3D 0) {
>                 dev_err(dev, "Missing reg in %s node\n", node->full_name)=
;
> +               put_device(&larb_pdev->dev);
>                 return -EINVAL;
>         }
>         comp->regs_pa =3D res.start;
> --
> 2.25.4
>