Commit 82068ede authored by Jouni Högander's avatar Jouni Högander Committed by Jani Nikula
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drm: New function to get luminance range based on static hdr metadata 



Split luminance min/max calculation using static hdr metadata from
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c:update_connector_ext_caps
into drm/drm_edid.c and use it during edid parsing. Calculated range is
stored into connector->display_info->luminance_range.

Add new data structure (drm_luminance_range_inf) to store luminance range
calculated using data from EDID's static hdr metadata block. Add this new
struct as a part of drm_display_info struct.

v3: Squashed adding drm_luminance_range_info patch here
v2: Calculate range during edid parsing

Cc: Roman Li <roman.li@amd.com>
Cc: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Mika Kahola <mika.kahola@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: default avatarJouni Högander <jouni.hogander@intel.com>
Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220719095700.14923-2-jouni.hogander@intel.com
parent e0686dc6

drivers/gpu/drm/drm_edid.c

+51 −1
Original line number Diff line number Diff line
@@ -5165,6 +5165,51 @@ static void fixup_detailed_cea_mode_clock(struct drm_display_mode *mode) 
	mode->clock = clock;

}



static void drm_calculate_luminance_range(struct drm_connector *connector)

{

	struct hdr_static_metadata *hdr_metadata = &connector->hdr_sink_metadata.hdmi_type1;

	struct drm_luminance_range_info *luminance_range =

		&connector->display_info.luminance_range;

	static const u8 pre_computed_values[] = {

		50, 51, 52, 53, 55, 56, 57, 58, 59, 61, 62, 63, 65, 66, 68, 69,

		71, 72, 74, 75, 77, 79, 81, 82, 84, 86, 88, 90, 92, 94, 96, 98

	};

	u32 max_avg, min_cll, max, min, q, r;



	if (!(hdr_metadata->metadata_type & BIT(HDMI_STATIC_METADATA_TYPE1)))

		return;



	max_avg = hdr_metadata->max_fall;

	min_cll = hdr_metadata->min_cll;



	/*

	 * From the specification (CTA-861-G), for calculating the maximum

	 * luminance we need to use:

	 *	Luminance = 50*2**(CV/32)

	 * Where CV is a one-byte value.

	 * For calculating this expression we may need float point precision;

	 * to avoid this complexity level, we take advantage that CV is divided

	 * by a constant. From the Euclids division algorithm, we know that CV

	 * can be written as: CV = 32*q + r. Next, we replace CV in the

	 * Luminance expression and get 50*(2**q)*(2**(r/32)), hence we just

	 * need to pre-compute the value of r/32. For pre-computing the values

	 * We just used the following Ruby line:

	 *	(0...32).each {|cv| puts (50*2**(cv/32.0)).round}

	 * The results of the above expressions can be verified at

	 * pre_computed_values.

	 */

	q = max_avg >> 5;

	r = max_avg % 32;

	max = (1 << q) * pre_computed_values[r];



	/* min luminance: maxLum * (CV/255)^2 / 100 */

	q = DIV_ROUND_CLOSEST(min_cll, 255);

	min = max * DIV_ROUND_CLOSEST((q * q), 100);



	luminance_range->min_luminance = min;

	luminance_range->max_luminance = max;

}



static uint8_t eotf_supported(const u8 *edid_ext)

{

	return edid_ext[2] &
@@ -5196,8 +5241,12 @@ drm_parse_hdr_metadata_block(struct drm_connector *connector, const u8 *db) 
		connector->hdr_sink_metadata.hdmi_type1.max_cll = db[4];

	if (len >= 5)

		connector->hdr_sink_metadata.hdmi_type1.max_fall = db[5];

	if (len >= 6)

	if (len >= 6) {

		connector->hdr_sink_metadata.hdmi_type1.min_cll = db[6];



		/* Calculate only when all values are available */

		drm_calculate_luminance_range(connector);

	}

}



static void
@@ -6101,6 +6150,7 @@ static void drm_reset_display_info(struct drm_connector *connector) 


	info->non_desktop = 0;

	memset(&info->monitor_range, 0, sizeof(info->monitor_range));

	memset(&info->luminance_range, 0, sizeof(info->luminance_range));



	info->mso_stream_count = 0;

	info->mso_pixel_overlap = 0;

include/drm/drm_connector.h

+21 −0
Original line number Diff line number Diff line
@@ -323,6 +323,22 @@ struct drm_monitor_range_info { 
	u8 max_vfreq;

};



/**

 * struct drm_luminance_range_info - Panel's luminance range for

 * &drm_display_info. Calculated using data in EDID

 *

 * This struct is used to store a luminance range supported by panel

 * as calculated using data from EDID's static hdr metadata.

 *

 * @min_luminance: This is the min supported luminance value

 *

 * @max_luminance: This is the max supported luminance value

 */

struct drm_luminance_range_info {

	u32 min_luminance;

	u32 max_luminance;

};



/**

 * enum drm_privacy_screen_status - privacy screen status

 *
@@ -624,6 +640,11 @@ struct drm_display_info { 
	 */

	struct drm_monitor_range_info monitor_range;



	/**

	 * @luminance_range: Luminance range supported by panel

	 */

	struct drm_luminance_range_info luminance_range;



	/**

	 * @mso_stream_count: eDP Multi-SST Operation (MSO) stream count from

	 * the DisplayID VESA vendor block. 0 for conventional Single-Stream