From 9b6067c08de84215d4c66a74150e9ac3e9f0ef72 Mon Sep 17 00:00:00 2001
From: Dmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>
Date: Fri, 19 Oct 2018 16:17:29 -0400
Subject: [PATCH] drm/amd/display: redesign scaling rotation math

Change the math to work in viewport rotation when calculating
viewport and viewport adjustment. This simplifies the math
for viewport calculation and makes viewport adjustment easier to
understand.

Signed-off-by: Dmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
---
 .../gpu/drm/amd/display/dc/core/dc_resource.c | 654 +++++++-----------
 1 file changed, 240 insertions(+), 414 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_resource.c b/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
index 98bc298ec948..0a1985ca9882 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
@@ -478,10 +478,29 @@ static enum pixel_format convert_pixel_format_to_dalsurface(
 	return dal_pixel_format;
 }
 
-static void rect_swap_helper(struct rect *rect)
-{
-	swap(rect->height, rect->width);
-	swap(rect->x, rect->y);
+static inline void get_vp_scan_direction(
+	enum dc_rotation_angle rotation,
+	bool horizontal_mirror,
+	bool *orthogonal_rotation,
+	bool *flip_vert_scan_dir,
+	bool *flip_horz_scan_dir)
+{
+	*orthogonal_rotation = false;
+	*flip_vert_scan_dir = false;
+	*flip_horz_scan_dir = false;
+	if (rotation == ROTATION_ANGLE_180) {
+		*flip_vert_scan_dir = true;
+		*flip_horz_scan_dir = true;
+	} else if (rotation == ROTATION_ANGLE_90) {
+		*orthogonal_rotation = true;
+		*flip_horz_scan_dir = true;
+	} else if (rotation == ROTATION_ANGLE_270) {
+		*orthogonal_rotation = true;
+		*flip_vert_scan_dir = true;
+	}
+
+	if (horizontal_mirror)
+		*flip_horz_scan_dir = !*flip_horz_scan_dir;
 }
 
 static void calculate_viewport(struct pipe_ctx *pipe_ctx)
@@ -490,33 +509,14 @@ static void calculate_viewport(struct pipe_ctx *pipe_ctx)
 	const struct dc_stream_state *stream = pipe_ctx->stream;
 	struct scaler_data *data = &pipe_ctx->plane_res.scl_data;
 	struct rect surf_src = plane_state->src_rect;
-	struct rect clip = { 0 };
+	struct rect clip, dest;
 	int vpc_div = (data->format == PIXEL_FORMAT_420BPP8
 			|| data->format == PIXEL_FORMAT_420BPP10) ? 2 : 1;
 	bool pri_split = pipe_ctx->bottom_pipe &&
 			pipe_ctx->bottom_pipe->plane_state == pipe_ctx->plane_state;
 	bool sec_split = pipe_ctx->top_pipe &&
 			pipe_ctx->top_pipe->plane_state == pipe_ctx->plane_state;
-	bool flip_vert_scan_dir = false, flip_horz_scan_dir = false;
-
-
-	/*
-	 * We need take horizontal mirror into account. On an unrotated surface this means
-	 * that the viewport offset is actually the offset from the other side of source
-	 * image so we have to subtract the right edge of the viewport from the right edge of
-	 * the source window. Similar to mirror we need to take into account how offset is
-	 * affected for 270/180 rotations
-	 */
-	if (pipe_ctx->plane_state->rotation == ROTATION_ANGLE_180) {
-		flip_vert_scan_dir = true;
-		flip_horz_scan_dir = true;
-	} else if (pipe_ctx->plane_state->rotation == ROTATION_ANGLE_90)
-		flip_vert_scan_dir = true;
-	else if (pipe_ctx->plane_state->rotation == ROTATION_ANGLE_270)
-		flip_horz_scan_dir = true;
-
-	if (pipe_ctx->plane_state->horizontal_mirror)
-		flip_horz_scan_dir = !flip_horz_scan_dir;
+	bool orthogonal_rotation, flip_y_start, flip_x_start;
 
 	if (stream->view_format == VIEW_3D_FORMAT_SIDE_BY_SIDE ||
 		stream->view_format == VIEW_3D_FORMAT_TOP_AND_BOTTOM) {
@@ -524,13 +524,10 @@ static void calculate_viewport(struct pipe_ctx *pipe_ctx)
 		sec_split = false;
 	}
 
-	if (pipe_ctx->plane_state->rotation == ROTATION_ANGLE_90 ||
-			pipe_ctx->plane_state->rotation == ROTATION_ANGLE_270)
-		rect_swap_helper(&surf_src);
-
 	/* The actual clip is an intersection between stream
 	 * source and surface clip
 	 */
+	dest = plane_state->dst_rect;
 	clip.x = stream->src.x > plane_state->clip_rect.x ?
 			stream->src.x : plane_state->clip_rect.x;
 
@@ -547,66 +544,77 @@ static void calculate_viewport(struct pipe_ctx *pipe_ctx)
 			stream->src.y + stream->src.height - clip.y :
 			plane_state->clip_rect.y + plane_state->clip_rect.height - clip.y ;
 
-	/* offset = surf_src.ofs + (clip.ofs - surface->dst_rect.ofs) * scl_ratio
-	 * note: surf_src.ofs should be added after rotation/mirror offset direction
-	 *       adjustment since it is already in viewport space
-	 * num_pixels = clip.num_pix * scl_ratio
+	/*
+	 * Need to calculate how scan origin is shifted in vp space
+	 * to correctly rotate clip and dst
 	 */
-	data->viewport.x = (clip.x - plane_state->dst_rect.x) *
-			surf_src.width / plane_state->dst_rect.width;
-	data->viewport.width = clip.width *
-			surf_src.width / plane_state->dst_rect.width;
+	get_vp_scan_direction(
+			plane_state->rotation,
+			plane_state->horizontal_mirror,
+			&orthogonal_rotation,
+			&flip_y_start,
+			&flip_x_start);
 
-	data->viewport.y = (clip.y - plane_state->dst_rect.y) *
-			surf_src.height / plane_state->dst_rect.height;
-	data->viewport.height = clip.height *
-			surf_src.height / plane_state->dst_rect.height;
-
-	if (flip_vert_scan_dir)
-		data->viewport.y = surf_src.height - data->viewport.y - data->viewport.height;
-	if (flip_horz_scan_dir)
-		data->viewport.x = surf_src.width - data->viewport.x - data->viewport.width;
+	if (orthogonal_rotation) {
+		swap(clip.x, clip.y);
+		swap(clip.width, clip.height);
+		swap(dest.x, dest.y);
+		swap(dest.width, dest.height);
+	}
+	if (flip_x_start) {
+		clip.x = dest.x + dest.width - clip.x - clip.width;
+		dest.x = 0;
+	}
+	if (flip_y_start) {
+		clip.y = dest.y + dest.height - clip.y - clip.height;
+		dest.y = 0;
+	}
 
-	data->viewport.x += surf_src.x;
-	data->viewport.y += surf_src.y;
+	/* offset = surf_src.ofs + (clip.ofs - surface->dst_rect.ofs) * scl_ratio
+	 * num_pixels = clip.num_pix * scl_ratio
+	 */
+	data->viewport.x = surf_src.x + (clip.x - dest.x) * surf_src.width / dest.width;
+	data->viewport.width = clip.width * surf_src.width / dest.width;
+
+	data->viewport.y = surf_src.y + (clip.y - dest.y) * surf_src.height / dest.height;
+	data->viewport.height = clip.height * surf_src.height / dest.height;
+
+	/* Handle split */
+	if (pri_split || sec_split) {
+		if (orthogonal_rotation) {
+			if (flip_y_start != pri_split)
+				data->viewport.height /= 2;
+			else {
+				data->viewport.y +=  data->viewport.height / 2;
+				/* Ceil offset pipe */
+				data->viewport.height = (data->viewport.height + 1) / 2;
+			}
+		} else {
+			if (flip_x_start != pri_split)
+				data->viewport.width /= 2;
+			else {
+				data->viewport.x +=  data->viewport.width / 2;
+				/* Ceil offset pipe */
+				data->viewport.width = (data->viewport.width + 1) / 2;
+			}
+		}
+	}
 
 	/* Round down, compensate in init */
 	data->viewport_c.x = data->viewport.x / vpc_div;
 	data->viewport_c.y = data->viewport.y / vpc_div;
-	data->inits.h_c = (data->viewport.x % vpc_div) != 0 ?
-			dc_fixpt_half : dc_fixpt_zero;
-	data->inits.v_c = (data->viewport.y % vpc_div) != 0 ?
-			dc_fixpt_half : dc_fixpt_zero;
+	data->inits.h_c = (data->viewport.x % vpc_div) != 0 ? dc_fixpt_half : dc_fixpt_zero;
+	data->inits.v_c = (data->viewport.y % vpc_div) != 0 ? dc_fixpt_half : dc_fixpt_zero;
+
 	/* Round up, assume original video size always even dimensions */
 	data->viewport_c.width = (data->viewport.width + vpc_div - 1) / vpc_div;
 	data->viewport_c.height = (data->viewport.height + vpc_div - 1) / vpc_div;
-
-	/* Handle hsplit */
-	if (sec_split) {
-		data->viewport.x +=  data->viewport.width / 2;
-		data->viewport_c.x +=  data->viewport_c.width / 2;
-		/* Ceil offset pipe */
-		data->viewport.width = (data->viewport.width + 1) / 2;
-		data->viewport_c.width = (data->viewport_c.width + 1) / 2;
-	} else if (pri_split) {
-		if (data->viewport.width > 1)
-			data->viewport.width /= 2;
-		if (data->viewport_c.width > 1)
-			data->viewport_c.width /= 2;
-	}
-
-	if (plane_state->rotation == ROTATION_ANGLE_90 ||
-			plane_state->rotation == ROTATION_ANGLE_270) {
-		rect_swap_helper(&data->viewport_c);
-		rect_swap_helper(&data->viewport);
-	}
 }
 
-static void calculate_recout(struct pipe_ctx *pipe_ctx, struct rect *recout_full)
+static void calculate_recout(struct pipe_ctx *pipe_ctx)
 {
 	const struct dc_plane_state *plane_state = pipe_ctx->plane_state;
 	const struct dc_stream_state *stream = pipe_ctx->stream;
-	struct rect surf_src = plane_state->src_rect;
 	struct rect surf_clip = plane_state->clip_rect;
 	bool pri_split = pipe_ctx->bottom_pipe &&
 			pipe_ctx->bottom_pipe->plane_state == pipe_ctx->plane_state;
@@ -614,10 +622,6 @@ static void calculate_recout(struct pipe_ctx *pipe_ctx, struct rect *recout_full
 			pipe_ctx->top_pipe->plane_state == pipe_ctx->plane_state;
 	bool top_bottom_split = stream->view_format == VIEW_3D_FORMAT_TOP_AND_BOTTOM;
 
-	if (pipe_ctx->plane_state->rotation == ROTATION_ANGLE_90 ||
-			pipe_ctx->plane_state->rotation == ROTATION_ANGLE_270)
-		rect_swap_helper(&surf_src);
-
 	pipe_ctx->plane_res.scl_data.recout.x = stream->dst.x;
 	if (stream->src.x < surf_clip.x)
 		pipe_ctx->plane_res.scl_data.recout.x += (surf_clip.x
@@ -646,7 +650,7 @@ static void calculate_recout(struct pipe_ctx *pipe_ctx, struct rect *recout_full
 			stream->dst.y + stream->dst.height
 						- pipe_ctx->plane_res.scl_data.recout.y;
 
-	/* Handle h & vsplit */
+	/* Handle h & v split, handle rotation using viewport */
 	if (sec_split && top_bottom_split) {
 		pipe_ctx->plane_res.scl_data.recout.y +=
 				pipe_ctx->plane_res.scl_data.recout.height / 2;
@@ -655,44 +659,14 @@ static void calculate_recout(struct pipe_ctx *pipe_ctx, struct rect *recout_full
 				(pipe_ctx->plane_res.scl_data.recout.height + 1) / 2;
 	} else if (pri_split && top_bottom_split)
 		pipe_ctx->plane_res.scl_data.recout.height /= 2;
-	else if (pri_split || sec_split) {
-		/* HMirror XOR Secondary_pipe XOR Rotation_180 */
-		bool right_view = (sec_split != plane_state->horizontal_mirror) !=
-					(plane_state->rotation == ROTATION_ANGLE_180);
-
-		if (plane_state->rotation == ROTATION_ANGLE_90
-				|| plane_state->rotation == ROTATION_ANGLE_270)
-			/* Secondary_pipe XOR Rotation_270 */
-			right_view = (plane_state->rotation == ROTATION_ANGLE_270) != sec_split;
-
-		if (right_view) {
-			pipe_ctx->plane_res.scl_data.recout.x +=
-					pipe_ctx->plane_res.scl_data.recout.width / 2;
-			/* Ceil offset pipe */
-			pipe_ctx->plane_res.scl_data.recout.width =
-					(pipe_ctx->plane_res.scl_data.recout.width + 1) / 2;
-		} else {
-			if (pipe_ctx->plane_res.scl_data.recout.width > 1)
-				pipe_ctx->plane_res.scl_data.recout.width /= 2;
-		}
-	}
-	/* Unclipped recout offset = stream dst offset + ((surf dst offset - stream surf_src offset)
-	 *			* 1/ stream scaling ratio) - (surf surf_src offset * 1/ full scl
-	 *			ratio)
-	 */
-	recout_full->x = stream->dst.x + (plane_state->dst_rect.x - stream->src.x)
-					* stream->dst.width / stream->src.width -
-			surf_src.x * plane_state->dst_rect.width / surf_src.width
-					* stream->dst.width / stream->src.width;
-	recout_full->y = stream->dst.y + (plane_state->dst_rect.y - stream->src.y)
-					* stream->dst.height / stream->src.height -
-			surf_src.y * plane_state->dst_rect.height / surf_src.height
-					* stream->dst.height / stream->src.height;
-
-	recout_full->width = plane_state->dst_rect.width
-					* stream->dst.width / stream->src.width;
-	recout_full->height = plane_state->dst_rect.height
-					* stream->dst.height / stream->src.height;
+	else if (sec_split) {
+		pipe_ctx->plane_res.scl_data.recout.x +=
+				pipe_ctx->plane_res.scl_data.recout.width / 2;
+		/* Ceil offset pipe */
+		pipe_ctx->plane_res.scl_data.recout.width =
+				(pipe_ctx->plane_res.scl_data.recout.width + 1) / 2;
+	} else if (pri_split)
+		pipe_ctx->plane_res.scl_data.recout.width /= 2;
 }
 
 static void calculate_scaling_ratios(struct pipe_ctx *pipe_ctx)
@@ -705,9 +679,10 @@ static void calculate_scaling_ratios(struct pipe_ctx *pipe_ctx)
 	const int out_w = stream->dst.width;
 	const int out_h = stream->dst.height;
 
+	/*Swap surf_src height and width since scaling ratios are in recout rotation*/
 	if (pipe_ctx->plane_state->rotation == ROTATION_ANGLE_90 ||
 			pipe_ctx->plane_state->rotation == ROTATION_ANGLE_270)
-		rect_swap_helper(&surf_src);
+		swap(surf_src.height, surf_src.width);
 
 	pipe_ctx->plane_res.scl_data.ratios.horz = dc_fixpt_from_fraction(
 					surf_src.width,
@@ -744,351 +719,202 @@ static void calculate_scaling_ratios(struct pipe_ctx *pipe_ctx)
 			pipe_ctx->plane_res.scl_data.ratios.vert_c, 19);
 }
 
-static void calculate_inits_and_adj_vp(struct pipe_ctx *pipe_ctx, struct rect *recout_full)
+static inline void adjust_vp_and_init_for_seamless_clip(
+		bool flip_scan_dir,
+		int recout_skip,
+		int src_size,
+		int taps,
+		struct fixed31_32 ratio,
+		struct fixed31_32 *init,
+		int *vp_offset,
+		int *vp_size)
 {
-	struct scaler_data *data = &pipe_ctx->plane_res.scl_data;
-	struct rect src = pipe_ctx->plane_state->src_rect;
-	int vpc_div = (data->format == PIXEL_FORMAT_420BPP8
-			|| data->format == PIXEL_FORMAT_420BPP10) ? 2 : 1;
-	bool flip_vert_scan_dir = false, flip_horz_scan_dir = false;
-
-	/*
-	 * Need to calculate the scan direction for viewport to make adjustments
-	 */
-	if (pipe_ctx->plane_state->rotation == ROTATION_ANGLE_180) {
-		flip_vert_scan_dir = true;
-		flip_horz_scan_dir = true;
-	} else if (pipe_ctx->plane_state->rotation == ROTATION_ANGLE_90)
-		flip_vert_scan_dir = true;
-	else if (pipe_ctx->plane_state->rotation == ROTATION_ANGLE_270)
-		flip_horz_scan_dir = true;
-
-	if (pipe_ctx->plane_state->horizontal_mirror)
-			flip_horz_scan_dir = !flip_horz_scan_dir;
-
-	if (pipe_ctx->plane_state->rotation == ROTATION_ANGLE_90 ||
-			pipe_ctx->plane_state->rotation == ROTATION_ANGLE_270) {
-		rect_swap_helper(&src);
-		rect_swap_helper(&data->viewport_c);
-		rect_swap_helper(&data->viewport);
-	}
-
-	/*
-	 * Init calculated according to formula:
-	 * 	init = (scaling_ratio + number_of_taps + 1) / 2
-	 * 	init_bot = init + scaling_ratio
-	 * 	init_c = init + truncated_vp_c_offset(from calculate viewport)
-	 */
-	data->inits.h = dc_fixpt_truncate(dc_fixpt_div_int(
-			dc_fixpt_add_int(data->ratios.horz, data->taps.h_taps + 1), 2), 19);
-
-	data->inits.h_c = dc_fixpt_truncate(dc_fixpt_add(data->inits.h_c, dc_fixpt_div_int(
-			dc_fixpt_add_int(data->ratios.horz_c, data->taps.h_taps_c + 1), 2)), 19);
-
-	data->inits.v = dc_fixpt_truncate(dc_fixpt_div_int(
-			dc_fixpt_add_int(data->ratios.vert, data->taps.v_taps + 1), 2), 19);
-
-	data->inits.v_c = dc_fixpt_truncate(dc_fixpt_add(data->inits.v_c, dc_fixpt_div_int(
-			dc_fixpt_add_int(data->ratios.vert_c, data->taps.v_taps_c + 1), 2)), 19);
-
-	if (!flip_horz_scan_dir) {
+	if (!flip_scan_dir) {
 		/* Adjust for viewport end clip-off */
-		if ((data->viewport.x + data->viewport.width) < (src.x + src.width)) {
-			int vp_clip = src.x + src.width - data->viewport.width - data->viewport.x;
-			int int_part = dc_fixpt_floor(
-					dc_fixpt_sub(data->inits.h, data->ratios.horz));
-
-			int_part = int_part > 0 ? int_part : 0;
-			data->viewport.width += int_part < vp_clip ? int_part : vp_clip;
-		}
-		if ((data->viewport_c.x + data->viewport_c.width) < (src.x + src.width) / vpc_div) {
-			int vp_clip = (src.x + src.width) / vpc_div -
-					data->viewport_c.width - data->viewport_c.x;
-			int int_part = dc_fixpt_floor(
-					dc_fixpt_sub(data->inits.h_c, data->ratios.horz_c));
+		if ((*vp_offset + *vp_size) < src_size) {
+			int vp_clip = src_size - *vp_size - *vp_offset;
+			int int_part = dc_fixpt_floor(dc_fixpt_sub(*init, ratio));
 
 			int_part = int_part > 0 ? int_part : 0;
-			data->viewport_c.width += int_part < vp_clip ? int_part : vp_clip;
+			*vp_size += int_part < vp_clip ? int_part : vp_clip;
 		}
 
 		/* Adjust for non-0 viewport offset */
-		if (data->viewport.x) {
+		if (*vp_offset) {
 			int int_part;
 
-			data->inits.h = dc_fixpt_add(data->inits.h, dc_fixpt_mul_int(
-					data->ratios.horz, data->recout.x - recout_full->x));
-			int_part = dc_fixpt_floor(data->inits.h) - data->viewport.x;
-			if (int_part < data->taps.h_taps) {
-				int int_adj = data->viewport.x >= (data->taps.h_taps - int_part) ?
-							(data->taps.h_taps - int_part) : data->viewport.x;
-				data->viewport.x -= int_adj;
-				data->viewport.width += int_adj;
+			*init = dc_fixpt_add(*init, dc_fixpt_mul_int(ratio, recout_skip));
+			int_part = dc_fixpt_floor(*init) - *vp_offset;
+			if (int_part < taps) {
+				int int_adj = *vp_offset >= (taps - int_part) ?
+							(taps - int_part) : *vp_offset;
+				*vp_offset -= int_adj;
+				*vp_size += int_adj;
 				int_part += int_adj;
-			} else if (int_part > data->taps.h_taps) {
-				data->viewport.x += int_part - data->taps.h_taps;
-				data->viewport.width -= int_part - data->taps.h_taps;
-				int_part = data->taps.h_taps;
+			} else if (int_part > taps) {
+				*vp_offset += int_part - taps;
+				*vp_size -= int_part - taps;
+				int_part = taps;
 			}
-			data->inits.h.value &= 0xffffffff;
-			data->inits.h = dc_fixpt_add_int(data->inits.h, int_part);
-		}
-
-		if (data->viewport_c.x) {
-			int int_part;
-
-			data->inits.h_c = dc_fixpt_add(data->inits.h_c, dc_fixpt_mul_int(
-					data->ratios.horz_c, data->recout.x - recout_full->x));
-			int_part = dc_fixpt_floor(data->inits.h_c) - data->viewport_c.x;
-			if (int_part < data->taps.h_taps_c) {
-				int int_adj = data->viewport_c.x >= (data->taps.h_taps_c - int_part) ?
-						(data->taps.h_taps_c - int_part) : data->viewport_c.x;
-				data->viewport_c.x -= int_adj;
-				data->viewport_c.width += int_adj;
-				int_part += int_adj;
-			} else if (int_part > data->taps.h_taps_c) {
-				data->viewport_c.x += int_part - data->taps.h_taps_c;
-				data->viewport_c.width -= int_part - data->taps.h_taps_c;
-				int_part = data->taps.h_taps_c;
-			}
-			data->inits.h_c.value &= 0xffffffff;
-			data->inits.h_c = dc_fixpt_add_int(data->inits.h_c, int_part);
+			init->value &= 0xffffffff;
+			*init = dc_fixpt_add_int(*init, int_part);
 		}
 	} else {
 		/* Adjust for non-0 viewport offset */
-		if (data->viewport.x) {
-			int int_part = dc_fixpt_floor(
-					dc_fixpt_sub(data->inits.h, data->ratios.horz));
-
-			int_part = int_part > 0 ? int_part : 0;
-			data->viewport.width += int_part < data->viewport.x ? int_part : data->viewport.x;
-			data->viewport.x -= int_part < data->viewport.x ? int_part : data->viewport.x;
-		}
-		if (data->viewport_c.x) {
-			int int_part = dc_fixpt_floor(
-					dc_fixpt_sub(data->inits.h_c, data->ratios.horz_c));
+		if (*vp_offset) {
+			int int_part = dc_fixpt_floor(dc_fixpt_sub(*init, ratio));
 
 			int_part = int_part > 0 ? int_part : 0;
-			data->viewport_c.width += int_part < data->viewport_c.x ? int_part : data->viewport_c.x;
-			data->viewport_c.x -= int_part < data->viewport_c.x ? int_part : data->viewport_c.x;
+			*vp_size += int_part < *vp_offset ? int_part : *vp_offset;
+			*vp_offset -= int_part < *vp_offset ? int_part : *vp_offset;
 		}
 
 		/* Adjust for viewport end clip-off */
-		if ((data->viewport.x + data->viewport.width) < (src.x + src.width)) {
+		if ((*vp_offset + *vp_size) < src_size) {
 			int int_part;
-			int end_offset = src.x + src.width
-					- data->viewport.x - data->viewport.width;
+			int end_offset = src_size - *vp_offset - *vp_size;
 
 			/*
 			 * this is init if vp had no offset, keep in mind this is from the
 			 * right side of vp due to scan direction
 			 */
-			data->inits.h = dc_fixpt_add(data->inits.h, dc_fixpt_mul_int(
-					data->ratios.horz, data->recout.x - recout_full->x));
+			*init = dc_fixpt_add(*init, dc_fixpt_mul_int(ratio, recout_skip));
 			/*
 			 * this is the difference between first pixel of viewport available to read
 			 * and init position, takning into account scan direction
 			 */
-			int_part = dc_fixpt_floor(data->inits.h) - end_offset;
-			if (int_part < data->taps.h_taps) {
-				int int_adj = end_offset >= (data->taps.h_taps - int_part) ?
-							(data->taps.h_taps - int_part) : end_offset;
-				data->viewport.width += int_adj;
+			int_part = dc_fixpt_floor(*init) - end_offset;
+			if (int_part < taps) {
+				int int_adj = end_offset >= (taps - int_part) ?
+							(taps - int_part) : end_offset;
+				*vp_size += int_adj;
 				int_part += int_adj;
-			} else if (int_part > data->taps.h_taps) {
-				data->viewport.width += int_part - data->taps.h_taps;
-				int_part = data->taps.h_taps;
+			} else if (int_part > taps) {
+				*vp_size += int_part - taps;
+				int_part = taps;
 			}
-			data->inits.h.value &= 0xffffffff;
-			data->inits.h = dc_fixpt_add_int(data->inits.h, int_part);
+			init->value &= 0xffffffff;
+			*init = dc_fixpt_add_int(*init, int_part);
 		}
-
-		if ((data->viewport_c.x + data->viewport_c.width) < (src.x + src.width) / vpc_div) {
-			int int_part;
-			int end_offset = (src.x + src.width) / vpc_div
-					- data->viewport_c.x - data->viewport_c.width;
-
-			/*
-			 * this is init if vp had no offset, keep in mind this is from the
-			 * right side of vp due to scan direction
-			 */
-			data->inits.h_c = dc_fixpt_add(data->inits.h_c, dc_fixpt_mul_int(
-					data->ratios.horz_c, data->recout.x - recout_full->x));
-			/*
-			 * this is the difference between first pixel of viewport available to read
-			 * and init position, takning into account scan direction
-			 */
-			int_part = dc_fixpt_floor(data->inits.h_c) - end_offset;
-			if (int_part < data->taps.h_taps_c) {
-				int int_adj = end_offset >= (data->taps.h_taps_c - int_part) ?
-							(data->taps.h_taps_c - int_part) : end_offset;
-				data->viewport_c.width += int_adj;
-				int_part += int_adj;
-			} else if (int_part > data->taps.h_taps_c) {
-				data->viewport_c.width += int_part - data->taps.h_taps_c;
-				int_part = data->taps.h_taps_c;
-			}
-			data->inits.h_c.value &= 0xffffffff;
-			data->inits.h_c = dc_fixpt_add_int(data->inits.h_c, int_part);
-		}
-
 	}
-	if (!flip_vert_scan_dir) {
-		/* Adjust for viewport end clip-off */
-		if ((data->viewport.y + data->viewport.height) < (src.y + src.height)) {
-			int vp_clip = src.y + src.height - data->viewport.height - data->viewport.y;
-			int int_part = dc_fixpt_floor(
-					dc_fixpt_sub(data->inits.v, data->ratios.vert));
-
-			int_part = int_part > 0 ? int_part : 0;
-			data->viewport.height += int_part < vp_clip ? int_part : vp_clip;
-		}
-		if ((data->viewport_c.y + data->viewport_c.height) < (src.y + src.height) / vpc_div) {
-			int vp_clip = (src.y + src.height) / vpc_div -
-					data->viewport_c.height - data->viewport_c.y;
-			int int_part = dc_fixpt_floor(
-					dc_fixpt_sub(data->inits.v_c, data->ratios.vert_c));
-
-			int_part = int_part > 0 ? int_part : 0;
-			data->viewport_c.height += int_part < vp_clip ? int_part : vp_clip;
-		}
-
-		/* Adjust for non-0 viewport offset */
-		if (data->viewport.y) {
-			int int_part;
-
-			data->inits.v = dc_fixpt_add(data->inits.v, dc_fixpt_mul_int(
-					data->ratios.vert, data->recout.y - recout_full->y));
-			int_part = dc_fixpt_floor(data->inits.v) - data->viewport.y;
-			if (int_part < data->taps.v_taps) {
-				int int_adj = data->viewport.y >= (data->taps.v_taps - int_part) ?
-							(data->taps.v_taps - int_part) : data->viewport.y;
-				data->viewport.y -= int_adj;
-				data->viewport.height += int_adj;
-				int_part += int_adj;
-			} else if (int_part > data->taps.v_taps) {
-				data->viewport.y += int_part - data->taps.v_taps;
-				data->viewport.height -= int_part - data->taps.v_taps;
-				int_part = data->taps.v_taps;
-			}
-			data->inits.v.value &= 0xffffffff;
-			data->inits.v = dc_fixpt_add_int(data->inits.v, int_part);
-		}
-
-		if (data->viewport_c.y) {
-			int int_part;
+}
 
-			data->inits.v_c = dc_fixpt_add(data->inits.v_c, dc_fixpt_mul_int(
-					data->ratios.vert_c, data->recout.y - recout_full->y));
-			int_part = dc_fixpt_floor(data->inits.v_c) - data->viewport_c.y;
-			if (int_part < data->taps.v_taps_c) {
-				int int_adj = data->viewport_c.y >= (data->taps.v_taps_c - int_part) ?
-						(data->taps.v_taps_c - int_part) : data->viewport_c.y;
-				data->viewport_c.y -= int_adj;
-				data->viewport_c.height += int_adj;
-				int_part += int_adj;
-			} else if (int_part > data->taps.v_taps_c) {
-				data->viewport_c.y += int_part - data->taps.v_taps_c;
-				data->viewport_c.height -= int_part - data->taps.v_taps_c;
-				int_part = data->taps.v_taps_c;
-			}
-			data->inits.v_c.value &= 0xffffffff;
-			data->inits.v_c = dc_fixpt_add_int(data->inits.v_c, int_part);
-		}
-	} else {
-		/* Adjust for non-0 viewport offset */
-		if (data->viewport.y) {
-			int int_part = dc_fixpt_floor(
-					dc_fixpt_sub(data->inits.v, data->ratios.vert));
+static void calculate_inits_and_adj_vp(struct pipe_ctx *pipe_ctx)
+{
+	const struct dc_plane_state *plane_state = pipe_ctx->plane_state;
+	const struct dc_stream_state *stream = pipe_ctx->stream;
+	struct scaler_data *data = &pipe_ctx->plane_res.scl_data;
+	struct rect src = pipe_ctx->plane_state->src_rect;
+	int recout_skip_h, recout_skip_v, surf_size_h, surf_size_v;
+	int vpc_div = (data->format == PIXEL_FORMAT_420BPP8
+			|| data->format == PIXEL_FORMAT_420BPP10) ? 2 : 1;
+	bool orthogonal_rotation, flip_vert_scan_dir, flip_horz_scan_dir;
 
-			int_part = int_part > 0 ? int_part : 0;
-			data->viewport.height += int_part < data->viewport.y ? int_part : data->viewport.y;
-			data->viewport.y -= int_part < data->viewport.y ? int_part : data->viewport.y;
-		}
-		if (data->viewport_c.y) {
-			int int_part = dc_fixpt_floor(
-					dc_fixpt_sub(data->inits.v_c, data->ratios.vert_c));
+	/*
+	 * Need to calculate the scan direction for viewport to make adjustments
+	 */
+	get_vp_scan_direction(
+			plane_state->rotation,
+			plane_state->horizontal_mirror,
+			&orthogonal_rotation,
+			&flip_vert_scan_dir,
+			&flip_horz_scan_dir);
+
+	/* Calculate src rect rotation adjusted to recout space */
+	surf_size_h = src.x + src.width;
+	surf_size_v = src.y + src.height;
+	if (flip_horz_scan_dir)
+		src.x = 0;
+	if (flip_vert_scan_dir)
+		src.y = 0;
+	if (orthogonal_rotation) {
+		swap(src.x, src.y);
+		swap(src.width, src.height);
+	}
 
-			int_part = int_part > 0 ? int_part : 0;
-			data->viewport_c.height += int_part < data->viewport_c.y ? int_part : data->viewport_c.y;
-			data->viewport_c.y -= int_part < data->viewport_c.y ? int_part : data->viewport_c.y;
-		}
+	/* Recout matching initial vp offset = recout_offset - (stream dst offset +
+	 *			((surf dst offset - stream src offset) * 1/ stream scaling ratio)
+	 *			- (surf surf_src offset * 1/ full scl ratio))
+	 */
+	recout_skip_h = data->recout.x - (stream->dst.x + (plane_state->dst_rect.x - stream->src.x)
+					* stream->dst.width / stream->src.width -
+					src.x * plane_state->dst_rect.width / src.width
+					* stream->dst.width / stream->src.width);
+	recout_skip_v = data->recout.y - (stream->dst.y + (plane_state->dst_rect.y - stream->src.y)
+					* stream->dst.height / stream->src.height -
+					src.y * plane_state->dst_rect.height / src.height
+					* stream->dst.height / stream->src.height);
+	if (orthogonal_rotation)
+		swap(recout_skip_h, recout_skip_v);
+	/*
+	 * Init calculated according to formula:
+	 * 	init = (scaling_ratio + number_of_taps + 1) / 2
+	 * 	init_bot = init + scaling_ratio
+	 * 	init_c = init + truncated_vp_c_offset(from calculate viewport)
+	 */
+	data->inits.h = dc_fixpt_truncate(dc_fixpt_div_int(
+			dc_fixpt_add_int(data->ratios.horz, data->taps.h_taps + 1), 2), 19);
 
-		/* Adjust for viewport end clip-off */
-		if ((data->viewport.y + data->viewport.height) < (src.y + src.height)) {
-			int int_part;
-			int end_offset = src.y + src.height
-					- data->viewport.y - data->viewport.height;
+	data->inits.h_c = dc_fixpt_truncate(dc_fixpt_add(data->inits.h_c, dc_fixpt_div_int(
+			dc_fixpt_add_int(data->ratios.horz_c, data->taps.h_taps_c + 1), 2)), 19);
 
-			/*
-			 * this is init if vp had no offset, keep in mind this is from the
-			 * right side of vp due to scan direction
-			 */
-			data->inits.v = dc_fixpt_add(data->inits.v, dc_fixpt_mul_int(
-					data->ratios.vert, data->recout.y - recout_full->y));
-			/*
-			 * this is the difference between first pixel of viewport available to read
-			 * and init position, taking into account scan direction
-			 */
-			int_part = dc_fixpt_floor(data->inits.v) - end_offset;
-			if (int_part < data->taps.v_taps) {
-				int int_adj = end_offset >= (data->taps.v_taps - int_part) ?
-							(data->taps.v_taps - int_part) : end_offset;
-				data->viewport.height += int_adj;
-				int_part += int_adj;
-			} else if (int_part > data->taps.v_taps) {
-				data->viewport.height += int_part - data->taps.v_taps;
-				int_part = data->taps.v_taps;
-			}
-			data->inits.v.value &= 0xffffffff;
-			data->inits.v = dc_fixpt_add_int(data->inits.v, int_part);
-		}
+	data->inits.v = dc_fixpt_truncate(dc_fixpt_div_int(
+			dc_fixpt_add_int(data->ratios.vert, data->taps.v_taps + 1), 2), 19);
 
-		if ((data->viewport_c.y + data->viewport_c.height) < (src.y + src.height) / vpc_div) {
-			int int_part;
-			int end_offset = (src.y + src.height) / vpc_div
-					- data->viewport_c.y - data->viewport_c.height;
+	data->inits.v_c = dc_fixpt_truncate(dc_fixpt_add(data->inits.v_c, dc_fixpt_div_int(
+			dc_fixpt_add_int(data->ratios.vert_c, data->taps.v_taps_c + 1), 2)), 19);
 
-			/*
-			 * this is init if vp had no offset, keep in mind this is from the
-			 * right side of vp due to scan direction
-			 */
-			data->inits.v_c = dc_fixpt_add(data->inits.v_c, dc_fixpt_mul_int(
-					data->ratios.vert_c, data->recout.y - recout_full->y));
-			/*
-			 * this is the difference between first pixel of viewport available to read
-			 * and init position, taking into account scan direction
-			 */
-			int_part = dc_fixpt_floor(data->inits.v_c) - end_offset;
-			if (int_part < data->taps.v_taps_c) {
-				int int_adj = end_offset >= (data->taps.v_taps_c - int_part) ?
-							(data->taps.v_taps_c - int_part) : end_offset;
-				data->viewport_c.height += int_adj;
-				int_part += int_adj;
-			} else if (int_part > data->taps.v_taps_c) {
-				data->viewport_c.height += int_part - data->taps.v_taps_c;
-				int_part = data->taps.v_taps_c;
-			}
-			data->inits.v_c.value &= 0xffffffff;
-			data->inits.v_c = dc_fixpt_add_int(data->inits.v_c, int_part);
-		}
-	}
+	/*
+	 * Taps, inits and scaling ratios are in recout space need to rotate
+	 * to viewport rotation before adjustment
+	 */
+	adjust_vp_and_init_for_seamless_clip(
+			flip_horz_scan_dir,
+			recout_skip_h,
+			surf_size_h,
+			orthogonal_rotation ? data->taps.v_taps : data->taps.h_taps,
+			orthogonal_rotation ? data->ratios.vert : data->ratios.horz,
+			orthogonal_rotation ? &data->inits.v : &data->inits.h,
+			&data->viewport.x,
+			&data->viewport.width);
+	adjust_vp_and_init_for_seamless_clip(
+			flip_horz_scan_dir,
+			recout_skip_h,
+			surf_size_h / vpc_div,
+			orthogonal_rotation ? data->taps.v_taps_c : data->taps.h_taps_c,
+			orthogonal_rotation ? data->ratios.vert_c : data->ratios.horz_c,
+			orthogonal_rotation ? &data->inits.v_c : &data->inits.h_c,
+			&data->viewport_c.x,
+			&data->viewport_c.width);
+	adjust_vp_and_init_for_seamless_clip(
+			flip_vert_scan_dir,
+			recout_skip_v,
+			surf_size_v,
+			orthogonal_rotation ? data->taps.h_taps : data->taps.v_taps,
+			orthogonal_rotation ? data->ratios.horz : data->ratios.vert,
+			orthogonal_rotation ? &data->inits.h : &data->inits.v,
+			&data->viewport.y,
+			&data->viewport.height);
+	adjust_vp_and_init_for_seamless_clip(
+			flip_vert_scan_dir,
+			recout_skip_v,
+			surf_size_v / vpc_div,
+			orthogonal_rotation ? data->taps.h_taps_c : data->taps.v_taps_c,
+			orthogonal_rotation ? data->ratios.horz_c : data->ratios.vert_c,
+			orthogonal_rotation ? &data->inits.h_c : &data->inits.v_c,
+			&data->viewport_c.y,
+			&data->viewport_c.height);
 
 	/* Interlaced inits based on final vert inits */
 	data->inits.v_bot = dc_fixpt_add(data->inits.v, data->ratios.vert);
 	data->inits.v_c_bot = dc_fixpt_add(data->inits.v_c, data->ratios.vert_c);
 
-	if (pipe_ctx->plane_state->rotation == ROTATION_ANGLE_90 ||
-			pipe_ctx->plane_state->rotation == ROTATION_ANGLE_270) {
-		rect_swap_helper(&data->viewport_c);
-		rect_swap_helper(&data->viewport);
-	}
 }
 
 bool resource_build_scaling_params(struct pipe_ctx *pipe_ctx)
 {
 	const struct dc_plane_state *plane_state = pipe_ctx->plane_state;
 	struct dc_crtc_timing *timing = &pipe_ctx->stream->timing;
-	struct rect recout_full = { 0 };
 	bool res = false;
 	DC_LOGGER_INIT(pipe_ctx->stream->ctx->logger);
 	/* Important: scaling ratio calculation requires pixel format,
@@ -1105,7 +931,7 @@ bool resource_build_scaling_params(struct pipe_ctx *pipe_ctx)
 	if (pipe_ctx->plane_res.scl_data.viewport.height < 16 || pipe_ctx->plane_res.scl_data.viewport.width < 16)
 		return false;
 
-	calculate_recout(pipe_ctx, &recout_full);
+	calculate_recout(pipe_ctx);
 
 	/**
 	 * Setting line buffer pixel depth to 24bpp yields banding
@@ -1146,7 +972,7 @@ bool resource_build_scaling_params(struct pipe_ctx *pipe_ctx)
 
 	if (res)
 		/* May need to re-check lb size after this in some obscure scenario */
-		calculate_inits_and_adj_vp(pipe_ctx, &recout_full);
+		calculate_inits_and_adj_vp(pipe_ctx);
 
 	DC_LOG_SCALER(
 				"%s: Viewport:\nheight:%d width:%d x:%d "
-- 
2.30.2