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From:   Chun-Kuang Hu <chunkuang.hu@kernel.org>
Date:   Sat, 24 Apr 2021 08:24:45 +0800
Message-ID: <CAAOTY_-N4D2PJR0-YG3r+tLg0kcFZh8zyN=7kBNJsghpZG4nDA@mail.gmail.com>
Subject: Re: [PATCH v3 4/5] gpu/drm: mediatek: hdmi: add optional limit on
 maximal HDMI mode clock
To:     Neil Armstrong <narmstrong@baylibre.com>
Cc:     Chun-Kuang Hu <chunkuang.hu@kernel.org>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        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>,
        Fabien Parent <fparent@baylibre.com>
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Hi, Neil:

Neil Armstrong <narmstrong@baylibre.com> =E6=96=BC 2021=E5=B9=B44=E6=9C=881=
9=E6=97=A5 =E9=80=B1=E4=B8=80 =E4=B8=8B=E5=8D=883:33=E5=AF=AB=E9=81=93=EF=
=BC=9A
>
> Some SoCs like the MT8167 have a hard limit on the maximal supported HDMI=
 TMDS
> clock, so add a configuration value to filter out those modes.

Reviewed-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>

>
> Signed-off-by: Fabien Parent <fparent@baylibre.com>
> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_hdmi.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_hdmi.c b/drivers/gpu/drm/mediat=
ek/mtk_hdmi.c
> index 0539262e69d3..bc50d97f2553 100644
> --- a/drivers/gpu/drm/mediatek/mtk_hdmi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_hdmi.c
> @@ -149,6 +149,7 @@ struct hdmi_audio_param {
>  struct mtk_hdmi_conf {
>         bool tz_disabled;
>         bool cea_modes_only;
> +       unsigned long max_mode_clock;
>  };
>
>  struct mtk_hdmi {
> @@ -1226,6 +1227,10 @@ static int mtk_hdmi_bridge_mode_valid(struct drm_b=
ridge *bridge,
>         if (hdmi->conf->cea_modes_only && !drm_match_cea_mode(mode))
>                 return MODE_BAD;
>
> +       if (hdmi->conf->max_mode_clock &&
> +           mode->clock > hdmi->conf->max_mode_clock)
> +               return MODE_CLOCK_HIGH;
> +
>         if (mode->clock < 27000)
>                 return MODE_CLOCK_LOW;
>         if (mode->clock > 297000)
> --
> 2.25.1
>