drm/amd/display: Fix the delta clamping for shaper LUT

The shaper LUT requires a 10-bit value of the delta between segments. We
were using dc_fixpt_clamp_u0d10() to do that but it doesn't do what we
want it to do. It will preserve 10-bit precision after the decimal
point, but that's not quite what we want. We want 14-bit precision and
discard the 4 most-significant bytes.

To do that we'll do dc_fixpt_clamp_u0d14() & 0x3ff instead.
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Reviewed-by: Krunoslav Kovac <krunoslav.kovac@amd.com>
Acked-by: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -308,7 +308,10 @@ bool cm_helper_convert_to_custom_float(
 #define NUMBER_REGIONS     32
 #define NUMBER_SW_SEGMENTS 16
 
-bool cm_helper_translate_curve_to_hw_format(
+#define DC_LOGGER \
+		ctx->logger
+
+bool cm_helper_translate_curve_to_hw_format(struct dc_context *ctx,
 				const struct dc_transfer_func *output_tf,
 				struct pwl_params *lut_params, bool fixpoint)
 {
@@ -482,10 +485,18 @@ bool cm_helper_translate_curve_to_hw_format(
 		rgb->delta_green = dc_fixpt_sub(rgb_plus_1->green, rgb->green);
 		rgb->delta_blue  = dc_fixpt_sub(rgb_plus_1->blue,  rgb->blue);
 
+
 		if (fixpoint == true) {
-			rgb->delta_red_reg   = dc_fixpt_clamp_u0d10(rgb->delta_red);
-			rgb->delta_green_reg = dc_fixpt_clamp_u0d10(rgb->delta_green);
-			rgb->delta_blue_reg  = dc_fixpt_clamp_u0d10(rgb->delta_blue);
+			uint32_t red_clamp = dc_fixpt_clamp_u0d14(rgb->delta_red);
+			uint32_t green_clamp = dc_fixpt_clamp_u0d14(rgb->delta_green);
+			uint32_t blue_clamp = dc_fixpt_clamp_u0d14(rgb->delta_blue);
+
+			if (red_clamp >> 10 || green_clamp >> 10 || blue_clamp >> 10)
+				DC_LOG_WARNING("Losing delta precision while programming shaper LUT.");
+
+			rgb->delta_red_reg   = red_clamp & 0x3ff;
+			rgb->delta_green_reg = green_clamp & 0x3ff;
+			rgb->delta_blue_reg  = blue_clamp & 0x3ff;
 			rgb->red_reg         = dc_fixpt_clamp_u0d14(rgb->red);
 			rgb->green_reg       = dc_fixpt_clamp_u0d14(rgb->green);
 			rgb->blue_reg        = dc_fixpt_clamp_u0d14(rgb->blue);

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

@@ -106,6 +106,7 @@ bool cm_helper_convert_to_custom_float(
 		bool fixpoint);
 
 bool cm_helper_translate_curve_to_hw_format(
+		struct dc_context *ctx,
 		const struct dc_transfer_func *output_tf,
 		struct pwl_params *lut_params, bool fixpoint);
 

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c

@@ -1843,7 +1843,7 @@ bool dcn10_set_output_transfer_func(struct dc *dc, struct pipe_ctx *pipe_ctx,
 	/* dcn10_translate_regamma_to_hw_format takes 750us, only do it when full
 	 * update.
 	 */
-	else if (cm_helper_translate_curve_to_hw_format(
+	else if (cm_helper_translate_curve_to_hw_format(dc->ctx,
 			stream->out_transfer_func,
 			&dpp->regamma_params, false)) {
 		dpp->funcs->dpp_program_regamma_pwl(

drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c

@@ -867,7 +867,7 @@ bool dcn20_set_output_transfer_func(struct dc *dc, struct pipe_ctx *pipe_ctx,
 			params = &stream->out_transfer_func->pwl;
 		else if (pipe_ctx->stream->out_transfer_func->type ==
 			TF_TYPE_DISTRIBUTED_POINTS &&
-			cm_helper_translate_curve_to_hw_format(
+			cm_helper_translate_curve_to_hw_format(dc->ctx,
 			stream->out_transfer_func,
 			&mpc->blender_params, false))
 			params = &mpc->blender_params;
@@ -896,7 +896,7 @@ bool dcn20_set_blend_lut(
 		if (plane_state->blend_tf->type == TF_TYPE_HWPWL)
 			blend_lut = &plane_state->blend_tf->pwl;
 		else if (plane_state->blend_tf->type == TF_TYPE_DISTRIBUTED_POINTS) {
-			cm_helper_translate_curve_to_hw_format(
+			cm_helper_translate_curve_to_hw_format(plane_state->ctx,
 					plane_state->blend_tf,
 					&dpp_base->regamma_params, false);
 			blend_lut = &dpp_base->regamma_params;
@@ -918,7 +918,7 @@ bool dcn20_set_shaper_3dlut(
 		if (plane_state->in_shaper_func->type == TF_TYPE_HWPWL)
 			shaper_lut = &plane_state->in_shaper_func->pwl;
 		else if (plane_state->in_shaper_func->type == TF_TYPE_DISTRIBUTED_POINTS) {
-			cm_helper_translate_curve_to_hw_format(
+			cm_helper_translate_curve_to_hw_format(plane_state->ctx,
 					plane_state->in_shaper_func,
 					&dpp_base->shaper_params, true);
 			shaper_lut = &dpp_base->shaper_params;

drivers/gpu/drm/amd/display/dc/dcn30/dcn30_dwb_cm.c

@@ -280,7 +280,7 @@ bool dwb3_ogam_set_input_transfer_func(
 	dwb_ogam_lut = kzalloc(sizeof(*dwb_ogam_lut), GFP_KERNEL);
 
 	if (dwb_ogam_lut) {
-		cm_helper_translate_curve_to_hw_format(
+		cm_helper_translate_curve_to_hw_format(dwbc->ctx,
 			in_transfer_func_dwb_ogam,
 			dwb_ogam_lut, false);
 

drivers/gpu/drm/amd/display/dc/dcn30/dcn30_hwseq.c

@@ -106,7 +106,7 @@ static bool dcn30_set_mpc_shaper_3dlut(struct pipe_ctx *pipe_ctx,
 		if (stream->func_shaper->type == TF_TYPE_HWPWL) {
 			shaper_lut = &stream->func_shaper->pwl;
 		} else if (stream->func_shaper->type == TF_TYPE_DISTRIBUTED_POINTS) {
-			cm_helper_translate_curve_to_hw_format(stream->func_shaper,
+			cm_helper_translate_curve_to_hw_format(stream->ctx, stream->func_shaper,
 							       &dpp_base->shaper_params, true);
 			shaper_lut = &dpp_base->shaper_params;
 		}

drivers/gpu/drm/amd/display/dc/dcn32/dcn32_hwseq.c

@@ -448,7 +448,7 @@ bool dcn32_set_mpc_shaper_3dlut(
 		if (stream->func_shaper->type == TF_TYPE_HWPWL)
 			shaper_lut = &stream->func_shaper->pwl;
 		else if (stream->func_shaper->type == TF_TYPE_DISTRIBUTED_POINTS) {
-			cm_helper_translate_curve_to_hw_format(
+			cm_helper_translate_curve_to_hw_format(stream->ctx,
 					stream->func_shaper,
 					&dpp_base->shaper_params, true);
 			shaper_lut = &dpp_base->shaper_params;
@@ -484,7 +484,7 @@ bool dcn32_set_mcm_luts(
 		if (plane_state->blend_tf->type == TF_TYPE_HWPWL)
 			lut_params = &plane_state->blend_tf->pwl;
 		else if (plane_state->blend_tf->type == TF_TYPE_DISTRIBUTED_POINTS) {
-			cm_helper_translate_curve_to_hw_format(
+			cm_helper_translate_curve_to_hw_format(plane_state->ctx,
 					plane_state->blend_tf,
 					&dpp_base->regamma_params, false);
 			lut_params = &dpp_base->regamma_params;
@@ -499,7 +499,7 @@ bool dcn32_set_mcm_luts(
 		else if (plane_state->in_shaper_func->type == TF_TYPE_DISTRIBUTED_POINTS) {
 			// TODO: dpp_base replace
 			ASSERT(false);
-			cm_helper_translate_curve_to_hw_format(
+			cm_helper_translate_curve_to_hw_format(plane_state->ctx,
 					plane_state->in_shaper_func,
 					&dpp_base->shaper_params, true);
 			lut_params = &dpp_base->shaper_params;