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From:   Chun-Kuang Hu <chunkuang.hu@kernel.org>
Date:   Mon, 4 Jul 2022 21:51:25 +0800
Message-ID: <CAAOTY__F2Ms6tfYgU=5wXS==0qVivo6OT=8txq9yA3XQLfqh-A@mail.gmail.com>
Subject: Re: [PATCH] drm/mediatek: ensure bridge disable happends before suspend
To:     Hsin-Yi Wang <hsinyi@chromium.org>
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>,
        DRI Development <dri-devel@lists.freedesktop.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@lists.infradead.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        linux-kernel <linux-kernel@vger.kernel.org>
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Hi, Hsin-yi:

Hsin-Yi Wang <hsinyi@chromium.org> =E6=96=BC 2022=E5=B9=B46=E6=9C=8830=E6=
=97=A5 =E9=80=B1=E5=9B=9B =E5=87=8C=E6=99=A83:06=E5=AF=AB=E9=81=93=EF=BC=9A
>
> Make sure bridge_disable will be called before suspend by calling
> drm_mode_config_helper_suspend() in .prepare callback.

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.

>
> Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
> ---
> The issue is found if suspend is called via VT2 in several MTK SoC (eg.
> MT8173, MT8183, MT8186) chromebook boards with eDP bridge:
> bridge disable is called through mtk-drm's suspend, and it needs to be
> called before bridge pm runtime suspend.
> So we move the hook to .prepare() and .complete().
> ---
>  drivers/gpu/drm/mediatek/mtk_drm_drv.c | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/med=
iatek/mtk_drm_drv.c
> index 13a1bbe7ead7f..a42812e490007 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> @@ -828,8 +828,7 @@ static int mtk_drm_remove(struct platform_device *pde=
v)
>         return 0;
>  }
>
> -#ifdef CONFIG_PM_SLEEP
> -static int mtk_drm_sys_suspend(struct device *dev)
> +static int mtk_drm_sys_prepare(struct device *dev)
>  {
>         struct mtk_drm_private *private =3D dev_get_drvdata(dev);
>         struct drm_device *drm =3D private->drm;
> @@ -840,20 +839,21 @@ static int mtk_drm_sys_suspend(struct device *dev)
>         return ret;
>  }
>
> -static int mtk_drm_sys_resume(struct device *dev)
> +static void mtk_drm_sys_complete(struct device *dev)
>  {
>         struct mtk_drm_private *private =3D dev_get_drvdata(dev);
>         struct drm_device *drm =3D private->drm;
>         int ret;
>
>         ret =3D drm_mode_config_helper_resume(drm);
> -
> -       return ret;
> +       if (ret)
> +               dev_err(dev, "Failed to resume\n");
>  }
> -#endif
>
> -static SIMPLE_DEV_PM_OPS(mtk_drm_pm_ops, mtk_drm_sys_suspend,
> -                        mtk_drm_sys_resume);
> +static const struct dev_pm_ops mtk_drm_pm_ops =3D {
> +       .prepare =3D mtk_drm_sys_prepare,
> +       .complete =3D mtk_drm_sys_complete,
> +};
>
>  static struct platform_driver mtk_drm_platform_driver =3D {
>         .probe  =3D mtk_drm_probe,
> --
> 2.37.0.rc0.161.g10f37bed90-goog
>