linux-kernel - Re: [PATCH] drm: Parse Colorimetry data block from EDID

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Message-ID: <20200827105701.GS6112@intel.com>
Date:   Thu, 27 Aug 2020 13:57:01 +0300
From:   Ville Syrjälä <ville.syrjala@...ux.intel.com>
To:     Algea Cao <algea.cao@...k-chips.com>
Cc:     mripard@...nel.org, tzimmermann@...e.de,
        linux-kernel@...r.kernel.org, airlied@...ux.ie,
        dri-devel@...ts.freedesktop.org, maarten.lankhorst@...ux.intel.com,
        daniel@...ll.ch, linux-rockchip@...ts.infradead.org
Subject: Re: [PATCH] drm: Parse Colorimetry data block from EDID

On Wed, Aug 26, 2020 at 10:23:28PM +0800, Algea Cao wrote:
> CEA 861.3 spec adds colorimetry data block for HDMI.
> Parsing the block to get the colorimetry data from
> panel.

And what exactly do you want to do with that data?

> 
> Signed-off-by: Algea Cao <algea.cao@...k-chips.com>
> ---
> 
>  drivers/gpu/drm/drm_edid.c  | 45 +++++++++++++++++++++++++++++++++++++
>  include/drm/drm_connector.h |  3 +++
>  include/drm/drm_edid.h      | 14 ++++++++++++
>  3 files changed, 62 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index 31496b6cfc56..67e607c04492 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -3223,6 +3223,7 @@ add_detailed_modes(struct drm_connector *connector, struct edid *edid,
>  #define VIDEO_BLOCK     0x02
>  #define VENDOR_BLOCK    0x03
>  #define SPEAKER_BLOCK	0x04
> +#define COLORIMETRY_DATA_BLOCK		0x5
>  #define HDR_STATIC_METADATA_BLOCK	0x6
>  #define USE_EXTENDED_TAG 0x07
>  #define EXT_VIDEO_CAPABILITY_BLOCK 0x00
> @@ -4309,6 +4310,48 @@ static void fixup_detailed_cea_mode_clock(struct drm_display_mode *mode)
>  	mode->clock = clock;
>  }
>  
> +static bool cea_db_is_hdmi_colorimetry_data_block(const u8 *db)
> +{
> +	if (cea_db_tag(db) != USE_EXTENDED_TAG)
> +		return false;
> +
> +	if (db[1] != COLORIMETRY_DATA_BLOCK)
> +		return false;
> +
> +	if (cea_db_payload_len(db) < 2)
> +		return false;
> +
> +	return true;
> +}
> +
> +static void
> +drm_parse_colorimetry_data_block(struct drm_connector *connector, const u8 *db)
> +{
> +	struct drm_hdmi_info *info = &connector->display_info.hdmi;
> +
> +	if (db[2] & DRM_EDID_CLRMETRY_xvYCC_601)
> +		info->colorimetry |= DRM_EDID_CLRMETRY_xvYCC_601;
> +	if (db[2] & DRM_EDID_CLRMETRY_xvYCC_709)
> +		info->colorimetry |= DRM_EDID_CLRMETRY_xvYCC_709;
> +	if (db[2] & DRM_EDID_CLRMETRY_sYCC_601)
> +		info->colorimetry |= DRM_EDID_CLRMETRY_sYCC_601;
> +	if (db[2] & DRM_EDID_CLRMETRY_ADBYCC_601)
> +		info->colorimetry |= DRM_EDID_CLRMETRY_ADBYCC_601;
> +	if (db[2] & DRM_EDID_CLRMETRY_ADB_RGB)
> +		info->colorimetry |= DRM_EDID_CLRMETRY_ADB_RGB;
> +	if (db[2] & DRM_EDID_CLRMETRY_BT2020_CYCC)
> +		info->colorimetry |= DRM_EDID_CLRMETRY_BT2020_CYCC;
> +	if (db[2] & DRM_EDID_CLRMETRY_BT2020_YCC)
> +		info->colorimetry |= DRM_EDID_CLRMETRY_BT2020_YCC;
> +	if (db[2] & DRM_EDID_CLRMETRY_BT2020_RGB)
> +		info->colorimetry |= DRM_EDID_CLRMETRY_BT2020_RGB;
> +	/* Byte 4 Bit 7: DCI-P3 */
> +	if (db[3] & BIT(7))
> +		info->colorimetry |= DRM_EDID_CLRMETRY_DCI_P3;
> +
> +	DRM_DEBUG_KMS("Supported Colorimetry 0x%x\n", info->colorimetry);
> +}
> +
>  static bool cea_db_is_hdmi_hdr_metadata_block(const u8 *db)
>  {
>  	if (cea_db_tag(db) != USE_EXTENDED_TAG)
> @@ -4994,6 +5037,8 @@ static void drm_parse_cea_ext(struct drm_connector *connector,
>  			drm_parse_vcdb(connector, db);
>  		if (cea_db_is_hdmi_hdr_metadata_block(db))
>  			drm_parse_hdr_metadata_block(connector, db);
> +		if (cea_db_is_hdmi_colorimetry_data_block(db))
> +			drm_parse_colorimetry_data_block(connector, db);
>  	}
>  }
>  
> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> index af145608b5ed..d599c3b9e881 100644
> --- a/include/drm/drm_connector.h
> +++ b/include/drm/drm_connector.h
> @@ -207,6 +207,9 @@ struct drm_hdmi_info {
>  
>  	/** @y420_dc_modes: bitmap of deep color support index */
>  	u8 y420_dc_modes;
> +
> +	/* @colorimetry: bitmap of supported colorimetry modes */
> +	u16 colorimetry;
>  };
>  
>  /**
> diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
> index cfa4f5af49af..98fa78c2f82d 100644
> --- a/include/drm/drm_edid.h
> +++ b/include/drm/drm_edid.h
> @@ -229,6 +229,20 @@ struct detailed_timing {
>  				    DRM_EDID_YCBCR420_DC_36 | \
>  				    DRM_EDID_YCBCR420_DC_30)
>  
> +/*
> + * Supported Colorimetry from colorimetry data block
> + * as per CEA 861-G spec
> + */
> +#define DRM_EDID_CLRMETRY_xvYCC_601   (1 << 0)
> +#define DRM_EDID_CLRMETRY_xvYCC_709   (1 << 1)
> +#define DRM_EDID_CLRMETRY_sYCC_601    (1 << 2)
> +#define DRM_EDID_CLRMETRY_ADBYCC_601  (1 << 3)
> +#define DRM_EDID_CLRMETRY_ADB_RGB     (1 << 4)
> +#define DRM_EDID_CLRMETRY_BT2020_CYCC (1 << 5)
> +#define DRM_EDID_CLRMETRY_BT2020_YCC  (1 << 6)
> +#define DRM_EDID_CLRMETRY_BT2020_RGB  (1 << 7)
> +#define DRM_EDID_CLRMETRY_DCI_P3      (1 << 15)
> +
>  /* ELD Header Block */
>  #define DRM_ELD_HEADER_BLOCK_SIZE	4
>  
> -- 
> 2.25.1
> 
> 
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@...ts.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Ville Syrjälä
Intel

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