Commit 34fa493a authored by Calvin Hou's avatar Calvin Hou Committed by Alex Deucher
Browse files

drm/amd/display: Correct algorithm for reversed gamma 

[Why]
DCN30 needs to correctly program reversed gamma curve, which DCN20
already has.
Also needs to fix a bug that 252-255 values are clipped.

[How]
Apply two fixes into DCN30.

Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/1513


Tested-by: default avatarDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: default avatarCalvin Hou <Calvin.Hou@amd.com>
Reviewed-by: default avatarJun Lei <Jun.Lei@amd.com>
Reviewed-by: default avatarKrunoslav Kovac <Krunoslav.Kovac@amd.com>
Acked-by: default avatarSolomon Chiu <solomon.chiu@amd.com>
Acked-by: default avatarVladimir Stempen <Vladimir.Stempen@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
parent 73076790

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

+18 −8
Original line number Diff line number Diff line
@@ -113,6 +113,7 @@ bool cm3_helper_translate_curve_to_hw_format( 
	struct pwl_result_data *rgb_resulted;

	struct pwl_result_data *rgb;

	struct pwl_result_data *rgb_plus_1;

	struct pwl_result_data *rgb_minus_1;

	struct fixed31_32 end_value;



	int32_t region_start, region_end;
@@ -140,7 +141,7 @@ bool cm3_helper_translate_curve_to_hw_format( 
		region_start = -MAX_LOW_POINT;

		region_end   = NUMBER_REGIONS - MAX_LOW_POINT;

	} else {

		/* 10 segments

		/* 11 segments

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

		 * There are less than 256 points, for optimization

		 */
@@ -154,9 +155,10 @@ bool cm3_helper_translate_curve_to_hw_format( 
		seg_distr[7] = 4;

		seg_distr[8] = 4;

		seg_distr[9] = 4;

		seg_distr[10] = 1;



		region_start = -10;

		region_end = 0;

		region_end = 1;

	}



	for (i = region_end - region_start; i < MAX_REGIONS_NUMBER ; i++)
@@ -189,6 +191,10 @@ bool cm3_helper_translate_curve_to_hw_format( 
	rgb_resulted[hw_points - 1].green = output_tf->tf_pts.green[start_index];

	rgb_resulted[hw_points - 1].blue = output_tf->tf_pts.blue[start_index];



	rgb_resulted[hw_points].red = rgb_resulted[hw_points - 1].red;

	rgb_resulted[hw_points].green = rgb_resulted[hw_points - 1].green;

	rgb_resulted[hw_points].blue = rgb_resulted[hw_points - 1].blue;



	// All 3 color channels have same x

	corner_points[0].red.x = dc_fixpt_pow(dc_fixpt_from_int(2),

					     dc_fixpt_from_int(region_start));
@@ -259,15 +265,18 @@ bool cm3_helper_translate_curve_to_hw_format( 


	rgb = rgb_resulted;

	rgb_plus_1 = rgb_resulted + 1;

	rgb_minus_1 = rgb;



	i = 1;

	while (i != hw_points + 1) {

		if (i >= hw_points - 1) {

			if (dc_fixpt_lt(rgb_plus_1->red, rgb->red))

			rgb_plus_1->red = rgb->red;

				rgb_plus_1->red = dc_fixpt_add(rgb->red, rgb_minus_1->delta_red);

			if (dc_fixpt_lt(rgb_plus_1->green, rgb->green))

			rgb_plus_1->green = rgb->green;

				rgb_plus_1->green = dc_fixpt_add(rgb->green, rgb_minus_1->delta_green);

			if (dc_fixpt_lt(rgb_plus_1->blue, rgb->blue))

			rgb_plus_1->blue = rgb->blue;

				rgb_plus_1->blue = dc_fixpt_add(rgb->blue, rgb_minus_1->delta_blue);

		}



		rgb->delta_red   = dc_fixpt_sub(rgb_plus_1->red,   rgb->red);

		rgb->delta_green = dc_fixpt_sub(rgb_plus_1->green, rgb->green);
@@ -283,6 +292,7 @@ bool cm3_helper_translate_curve_to_hw_format( 
		}



		++rgb_plus_1;

		rgb_minus_1 = rgb;

		++rgb;

		++i;

	}