drm/amd/display: fix split viewport rounding error

Signed-off-by: Dmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/calcs/dcn_calcs.c

@@ -890,6 +890,10 @@ bool dcn_validate_bandwidth(
 						+ pipe->bottom_pipe->plane_res.scl_data.recout.width;
 			}
 
+			ASSERT(pipe->plane_res.scl_data.ratios.horz.value != dal_fixed31_32_one.value
+				|| v->scaler_rec_out_width[input_idx] == v->viewport_width[input_idx]);
+			ASSERT(pipe->plane_res.scl_data.ratios.vert.value != dal_fixed31_32_one.value
+				|| v->scaler_recout_height[input_idx] == v->viewport_height[input_idx]);
 			v->dcc_enable[input_idx] = pipe->plane_state->dcc.enable ? dcn_bw_yes : dcn_bw_no;
 			v->source_pixel_format[input_idx] = tl_pixel_format_to_bw_defs(
 					pipe->plane_state->format);

drivers/gpu/drm/amd/display/dc/core/dc_resource.c

@@ -516,13 +516,11 @@ static void calculate_viewport(struct pipe_ctx *pipe_ctx)
 			right_view = (plane_state->rotation == ROTATION_ANGLE_270) != sec_split;
 
 		if (right_view) {
-			data->viewport.width /= 2;
-			data->viewport_c.width /= 2;
-			data->viewport.x +=  data->viewport.width;
-			data->viewport_c.x +=  data->viewport_c.width;
+			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 % 2;
-			data->viewport_c.width += data->viewport_c.width % 2;
+			data->viewport.width = (data->viewport.width + 1) / 2;
+			data->viewport_c.width = (data->viewport_c.width + 1) / 2;
 		} else {
 			data->viewport.width /= 2;
 			data->viewport_c.width /= 2;