Commit eda7f2e9 authored by Peterson's avatar Peterson Committed by Alex Deucher
Browse files

drm/amd/display: Fix low black values by increasing error 



[WHY]
Regamma resolution for the first few black levels can have problems for
calibration.

[HOW]
HW LUT is divided into N power-of-2 regions each with K segments.  For
SDR mode we set min point at 2^-10 and increments of 2^-13. It's
generally more than 8-bit SDR needs, but some calibration tools and API
use 12-bit curves.
The fix shifts starting point to 2^-12 and starting increments at 2^-16.

Reviewed-by: default avatarKrunoslav Kovac <krunoslav.kovac@amd.com>
Signed-off-by: default avatarPeterson <peterson.guo@amd.com>
Signed-off-by: default avatarRodrigo Siqueira <rodrigo.siqueira@amd.com>
Tested-by: default avatarDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent 21b673da

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_cm_common.c

+10 −15
Original line number Diff line number Diff line
@@ -365,23 +365,18 @@ bool cm_helper_translate_curve_to_hw_format(struct dc_context *ctx, 
		region_start = -MAX_LOW_POINT;

		region_end   = NUMBER_REGIONS - MAX_LOW_POINT;

	} else {

		/* 11 segments

		 * segment is from 2^-10 to 2^1

		/* 13 segments

		 * segment is from 2^-12 to 2^0

		 * There are less than 256 points, for optimization

		 */

		seg_distr[0] = 3;

		seg_distr[1] = 4;

		seg_distr[2] = 4;

		seg_distr[3] = 4;

		seg_distr[4] = 4;

		seg_distr[5] = 4;

		seg_distr[6] = 4;

		seg_distr[7] = 4;

		seg_distr[8] = 4;

		seg_distr[9] = 4;

		seg_distr[10] = 1;



		region_start = -10;

		const uint8_t SEG_COUNT = 12;



		for (i = 0; i < SEG_COUNT; i++)

			seg_distr[i] = 4;



		seg_distr[SEG_COUNT] = 1;



		region_start = -SEG_COUNT;

		region_end = 1;

	}

drivers/gpu/drm/amd/display/dc/dcn30/dcn30_cm_common.c

+10 −15
Original line number Diff line number Diff line
@@ -140,23 +140,18 @@ bool cm3_helper_translate_curve_to_hw_format( 
		region_start = -MAX_LOW_POINT;

		region_end   = NUMBER_REGIONS - MAX_LOW_POINT;

	} else {

		/* 11 segments

		 * segment is from 2^-10 to 2^0

		/* 13 segments

		 * segment is from 2^-12 to 2^0

		 * There are less than 256 points, for optimization

		 */

		seg_distr[0] = 3;

		seg_distr[1] = 4;

		seg_distr[2] = 4;

		seg_distr[3] = 4;

		seg_distr[4] = 4;

		seg_distr[5] = 4;

		seg_distr[6] = 4;

		seg_distr[7] = 4;

		seg_distr[8] = 4;

		seg_distr[9] = 4;

		seg_distr[10] = 1;



		region_start = -10;

		const uint8_t SEG_COUNT = 12;



		for (i = 0; i < SEG_COUNT; i++)

			seg_distr[i] = 4;



		seg_distr[SEG_COUNT] = 1;



		region_start = -SEG_COUNT;

		region_end = 1;

	}