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

[abhinavk@codeaurora.org]

Hi Ville

On 2020-01-24 06:36, Ville Syrjälä wrote:
> On Thu, Jan 23, 2020 at 02:40:45PM -0800, Abhinav Kumar wrote:
>> From: Uma Shankar <uma.shankar@intel.com>
>> 
>> CEA 861.3 spec adds colorimetry data block for HDMI.
>> Parsing the block to get the colorimetry data from
>> panel.
> 
> Why?
[Abhinav] The display driver for MSM chipsets still replies on the 
drm_edid.c for the parsing of
CEA extension blocks. Primarily we are using this information to know 
the supported colorspaces of the sink
(BT2020/DCI-P3) for use-cases such as HDR. The parts of the MSM display 
driver which use this block shall be posted
upstream a little bit later when our changes are ready to be posted.
Hence we would like drm_edid.c to be capable of parsing this block.
Thanks.

> 
>> 
>> This was posted by Uma Shankar at
>> https://patchwork.kernel.org/patch/10861327/
>> 
>> Modified by Abhinav Kumar:
>> - Use macros to distinguish the bit fields for clarity
>> 
>> Signed-off-by: Uma Shankar <uma.shankar@intel.com>
>> Signed-off-by: Abhinav Kumar <abhinavk@codeaurora.org>
>> ---
>>  drivers/gpu/drm/drm_edid.c  | 54 
>> +++++++++++++++++++++++++++++++++++++++++++++
>>  include/drm/drm_connector.h |  3 +++
>>  include/drm/drm_edid.h      | 11 +++++++++
>>  3 files changed, 68 insertions(+)
>> 
>> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
>> index 99769d6..148bfa4 100644
>> --- a/drivers/gpu/drm/drm_edid.c
>> +++ b/drivers/gpu/drm/drm_edid.c
>> @@ -3136,6 +3136,7 @@ static int drm_cvt_modes(struct drm_connector 
>> *connector,
>>  #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
>> @@ -4199,6 +4200,57 @@ 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;
>> +
>> +	/* As per CEA 861-G spec */
>> +	/* Byte 3 Bit 0: xvYCC_601 */
>> +	if (db[2] & BIT(0))
>> +		info->colorimetry |= DRM_EDID_CLRMETRY_xvYCC_601;
>> +	/* Byte 3 Bit 1: xvYCC_709 */
>> +	if (db[2] & BIT(1))
>> +		info->colorimetry |= DRM_EDID_CLRMETRY_xvYCC_709;
>> +	/* Byte 3 Bit 2: sYCC_601 */
>> +	if (db[2] & BIT(2))
>> +		info->colorimetry |= DRM_EDID_CLRMETRY_sYCC_601;
>> +	/* Byte 3 Bit 3: ADBYCC_601 */
>> +	if (db[2] & BIT(3))
>> +		info->colorimetry |= DRM_EDID_CLRMETRY_ADBYCC_601;
>> +	/* Byte 3 Bit 4: ADB_RGB */
>> +	if (db[2] & BIT(4))
>> +		info->colorimetry |= DRM_EDID_CLRMETRY_ADB_RGB;
>> +	/* Byte 3 Bit 5: BT2020_CYCC */
>> +	if (db[2] & BIT(5))
>> +		info->colorimetry |= DRM_EDID_CLRMETRY_BT2020_CYCC;
>> +	/* Byte 3 Bit 6: BT2020_YCC */
>> +	if (db[2] & BIT(6))
>> +		info->colorimetry |= DRM_EDID_CLRMETRY_BT2020_YCC;
>> +	/* Byte 3 Bit 7: BT2020_RGB */
>> +	if (db[2] & BIT(7))
>> +		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)
>> @@ -4877,6 +4929,8 @@ 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 2219109..a996ee3 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 f0b03d4..6168c1c 100644
>> --- a/include/drm/drm_edid.h
>> +++ b/include/drm/drm_edid.h
>> @@ -224,6 +224,17 @@ struct detailed_timing {
>>  				    DRM_EDID_YCBCR420_DC_36 | \
>>  				    DRM_EDID_YCBCR420_DC_30)
>> 
>> +/* Supported Colorimetry from colorimetry data block */
>> +#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
>> 
>> --
>> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora 
>> Forum,
>> a Linux Foundation Collaborative Project
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