Re: [PATCH 1/3] drm/meson: dw-hdmi: change YUV420 selection logic at clock setup

From: Neil Armstrong <neil.armstrong@linaro.org>
To: "Adrián Larumbe" <adrian.larumbe@collabora.com>,
	narmstrong@baylibre.com, khilman@baylibre.com,
	linux-amlogic@lists.infradead.org,
	dri-devel@lists.freedesktop.org, rfoss@kernel.org,
	andrzej.hajda@intel.com
Cc: kernel@collabora.com
Subject: Re: [PATCH 1/3] drm/meson: dw-hdmi: change YUV420 selection logic at clock setup
Date: Tue, 30 May 2023 09:48:46 +0200	[thread overview]
Message-ID: <b632ba5b-bbd6-aead-058f-f7466499239a@linaro.org> (raw)
In-Reply-To: <20230528140001.1057084-2-adrian.larumbe@collabora.com>

On 28/05/2023 15:59, Adrián Larumbe wrote:
> Right now clocking value selection code is prioritising RGB, YUV444 modes
> over YUV420 for HDMI2 sinks. However, because of the bus format selection
> procedure in dw-hdmi, for HDMI2 sinks YUV420 is the format that will always
> be picked during the drm bridge chain check stage.
> 
> Later on dw_hdmi_setup will configure a colour space based on the bus
> format that doesn't match the pixel value we had calculated as described
> above.
> 
> Fix it by bringing back dw-hdmi bus format check when picking the right
> pixel clock.
> 
> Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>
> ---
>   drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 6 ++++++
>   drivers/gpu/drm/meson/meson_dw_hdmi.c     | 4 ++--
>   include/drm/bridge/dw_hdmi.h              | 2 ++
>   3 files changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> index 603bb3c51027..d59a547f9cb2 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> @@ -3346,6 +3346,12 @@ static int dw_hdmi_parse_dt(struct dw_hdmi *hdmi)
>   	return 0;
>   }
>   
> +bool dw_hdmi_bus_fmt_is_420(struct dw_hdmi *hdmi)
> +{
> +	return hdmi_bus_fmt_is_yuv420(hdmi->hdmi_data.enc_out_bus_format);
> +}
> +EXPORT_SYMBOL_GPL(dw_hdmi_bus_fmt_is_420);
> +
>   struct dw_hdmi *dw_hdmi_probe(struct platform_device *pdev,
>   			      const struct dw_hdmi_plat_data *plat_data)
>   {
> diff --git a/drivers/gpu/drm/meson/meson_dw_hdmi.c b/drivers/gpu/drm/meson/meson_dw_hdmi.c
> index 3d046878ce6c..b49bb0d86efe 100644
> --- a/drivers/gpu/drm/meson/meson_dw_hdmi.c
> +++ b/drivers/gpu/drm/meson/meson_dw_hdmi.c
> @@ -379,8 +379,8 @@ static int dw_hdmi_phy_init(struct dw_hdmi *hdmi, void *data,
>   			 mode->clock > 340000 ? 40 : 10);
>   
>   	if (drm_mode_is_420_only(display, mode) ||
> -	    (!is_hdmi2_sink &&
> -	     drm_mode_is_420_also(display, mode)))
> +	    (!is_hdmi2_sink && drm_mode_is_420_also(display, mode)) ||
> +	    dw_hdmi_bus_fmt_is_420(hdmi))
>   		mode_is_420 = true;
>   
>   	/* Enable clocks */
> diff --git a/include/drm/bridge/dw_hdmi.h b/include/drm/bridge/dw_hdmi.h
> index f668e75fbabe..6a46baa0737c 100644
> --- a/include/drm/bridge/dw_hdmi.h
> +++ b/include/drm/bridge/dw_hdmi.h
> @@ -206,4 +206,6 @@ void dw_hdmi_phy_update_hpd(struct dw_hdmi *hdmi, void *data,
>   			    bool force, bool disabled, bool rxsense);
>   void dw_hdmi_phy_setup_hpd(struct dw_hdmi *hdmi, void *data);
>   
> +bool dw_hdmi_bus_fmt_is_420(struct dw_hdmi *hdmi);
> +
>   #endif /* __IMX_HDMI_H__ */

Acked-by: Neil Armstrong <neil.armstrong@linaro.org>

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