Re: [PATCH 3/6] drm/edid: detect SCDC support in HF-VSDB

From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: Shashank Sharma <shashank.sharma@intel.com>
Cc: jose.abreu@synopsys.com, =daniel.vetter@intel.com,
	intel-gfx@lists.freedesktop.org, thierry.reding@gmail.com,
	dri-devel@lists.freedesktop.org
Subject: Re: [PATCH 3/6] drm/edid: detect SCDC support in HF-VSDB
Date: Wed, 1 Feb 2017 18:33:41 +0200	[thread overview]
Message-ID: <20170201163340.GA31595@intel.com> (raw)
In-Reply-To: <1485953081-7630-4-git-send-email-shashank.sharma@intel.com>

On Wed, Feb 01, 2017 at 06:14:38PM +0530, Shashank Sharma wrote:
> This patch does following:
> - Adds a new structure (drm_hdmi_info) in drm_display_info.
>   This structure will be used to save and indicate if sink
>   supports advance HDMI 2.0 features
> - Checks the HF-VSDB block for presence of SCDC, and marks it
>   in hdmi_info structure.
> - If SCDC is present, checks if sink is capable of generating
>   scdc read request, and marks it in hdmi_info structure.
> 
> Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
> ---
>  drivers/gpu/drm/drm_edid.c  | 14 ++++++++++++++
>  include/drm/drm_connector.h | 26 ++++++++++++++++++++++++++
>  2 files changed, 40 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index 96d3e47..37902e5 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -3802,6 +3802,18 @@ enum hdmi_quantization_range
>  }
>  EXPORT_SYMBOL(drm_default_rgb_quant_range);
>  
> +static void drm_detect_hdmi_scdc(struct drm_connector *connector,
> +				 const u8 *hf_vsdb)
> +{
> +	struct drm_hdmi_info *hdmi = &connector->display_info.hdmi_info;
> +
> +	if (hf_vsdb[6] & 0x80) {
> +		hdmi->scdc_supported = true;
> +		if (hf_vsdb[6] & 0x40)
> +			hdmi->scdc_rr = true;
> +	}
> +}
> +
>  static void drm_parse_hdmi_deep_color_info(struct drm_connector *connector,
>  					   const u8 *hdmi)
>  {
> @@ -3916,6 +3928,8 @@ static void drm_parse_cea_ext(struct drm_connector *connector,
>  
>  		if (cea_db_is_hdmi_vsdb(db))
>  			drm_parse_hdmi_vsdb_video(connector, db);
> +		if (cea_db_is_hdmi_forum_vsdb(db))
> +			drm_detect_hdmi_scdc(connector, db);
>  	}
>  }
>  
> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> index e5e1edd..2435598 100644
> --- a/include/drm/drm_connector.h
> +++ b/include/drm/drm_connector.h
> @@ -87,6 +87,27 @@ enum subpixel_order {
>  	SubPixelVerticalRGB,
>  	SubPixelVerticalBGR,
>  	SubPixelNone,
> +
> +};
> +
> +/**
> + * struct drm_hdmi_info - runtime data about the connected sink
> + *
> + * Describes if a given hdmi display supports advance HDMI 2.0 featutes.
> + * This information is available in CEA-861-F extension blocks (like
> + * HF-VSDB)
> + * For sinks which provide an EDID this can be filled out by calling
> + * drm_add_edid_modes().
> + */
> +struct drm_hdmi_info {
> +	/**
> +	 * @scdc_supported: status control & data channel present.
> +	 */
> +	bool scdc_supported;
> +	/**
> +	 * @scdc_rr: sink is capable of generating scdc read request.
> +	 */
> +	bool scdc_rr;

Probably worth spelling the thing out.

>  };
>  
>  /**
> @@ -188,6 +209,11 @@ struct drm_display_info {
>  	 * @cea_rev: CEA revision of the HDMI sink.
>  	 */
>  	u8 cea_rev;
> +
> +	/**
> +	 * @hdmi_info: advance features of a HDMI sink.
> +	 */
> +	struct drm_hdmi_info hdmi_info;
>  };
>  
>  int drm_display_info_set_bus_formats(struct drm_display_info *info,
> -- 
> 1.9.1

-- 
Ville Syrjälä
Intel OTC
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