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Date:   Mon, 31 Aug 2020 22:53:16 +0300
From:   Ville =?iso-8859-1?Q?Syrj=E4l=E4?= <ville.syrjala@linux.intel.com>
To:     crj <algea.cao@rock-chips.com>
Cc:     mripard@kernel.org, tzimmermann@suse.de,
        linux-kernel@vger.kernel.org, airlied@linux.ie,
        dri-devel@lists.freedesktop.org, maarten.lankhorst@linux.intel.com,
        daniel@ffwll.ch, linux-rockchip@lists.infradead.org
Subject: Re: [PATCH] drm: Parse Colorimetry data block from EDID
Message-ID: <20200831195316.GC6112@intel.com>
References: <20200826142328.131144-1-algea.cao@rock-chips.com>
 <20200827105701.GS6112@intel.com>
 <4cadf318-cfc3-92d6-6219-170166db94ce@rock-chips.com>
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On Fri, Aug 28, 2020 at 09:07:13AM +0800, crj wrote:
> Hi Ville Syrjälä,
> 
> 在 2020/8/27 18:57, Ville Syrjälä 写道:
> > 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?
> 
> 
> We can get colorimetry data block from edid then support
> 
> HDMI colorimetry such as BT2020.

But what do you want to do with it? The patch does nothing
functional.

> 
> >> Signed-off-by: Algea Cao <algea.cao@rock-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@lists.freedesktop.org
> >> https://lists.freedesktop.org/mailman/listinfo/dri-devel
> 

-- 
Ville Syrjälä
Intel