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References: <20210206135020.1991820-1-heiko@sntech.de>
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From:   Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Date:   Fri, 19 Feb 2021 13:16:49 -0300
Message-ID: <CAAEAJfB44mBxbdHgXFV1m6774O+6jYR6jG2qYz_15+Vc1dNejA@mail.gmail.com>
Subject: Re: [PATCH] drm/panel: kd35t133: allow using non-continuous dsi clock
To:     Heiko Stuebner <heiko@sntech.de>
Cc:     Thierry Reding <thierry.reding@gmail.com>,
        Sam Ravnborg <sam@ravnborg.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        Chris Morgan <macromorgan@hotmail.com>
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On Sat, 6 Feb 2021 at 10:50, Heiko Stuebner <heiko@sntech.de> wrote:
>
> The panel is able to work when dsi clock is non-continuous, thus
> the system power consumption can be reduced using such feature.
>
> Add MIPI_DSI_CLOCK_NON_CONTINUOUS to panel's mode_flags.
>
> Also the flag actually becomes necessary after
> commit c6d94e37bdbb ("drm/bridge/synopsys: dsi: add support for non-continuous HS clock")
> and without it the panel only emits stripes instead of output.
>

Looks like c6d94e37bdbb landed in v5.10, so we should add:

Fixes: c6d94e37bdbb ("drm/bridge/synopsys: dsi: add support for
non-continuous HS clock")
Cc: stable@vger.kernel.org # 5.10+

With this fix, my Odroid Go2 has display.

Tested-by: Ezequiel Garcia <ezequiel@collabora.com>

Thanks,
Ezequiel

> Signed-off-by: Heiko Stuebner <heiko@sntech.de>
> ---
>  drivers/gpu/drm/panel/panel-elida-kd35t133.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/panel/panel-elida-kd35t133.c b/drivers/gpu/drm/panel/panel-elida-kd35t133.c
> index bc36aa3c1123..fe5ac3ef9018 100644
> --- a/drivers/gpu/drm/panel/panel-elida-kd35t133.c
> +++ b/drivers/gpu/drm/panel/panel-elida-kd35t133.c
> @@ -265,7 +265,8 @@ static int kd35t133_probe(struct mipi_dsi_device *dsi)
>         dsi->lanes = 1;
>         dsi->format = MIPI_DSI_FMT_RGB888;
>         dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_BURST |
> -                         MIPI_DSI_MODE_LPM | MIPI_DSI_MODE_EOT_PACKET;
> +                         MIPI_DSI_MODE_LPM | MIPI_DSI_MODE_EOT_PACKET |
> +                         MIPI_DSI_CLOCK_NON_CONTINUOUS;
>
>         drm_panel_init(&ctx->panel, &dsi->dev, &kd35t133_funcs,
>                        DRM_MODE_CONNECTOR_DSI);
> --
> 2.29.2
>
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