amd/drm/display: avoid dcn3 on flip opp change for slave pipes

At the moment on flip opp reassignment does not work in all cases
for non root pipes.
This change simply makes sure we prefer pipes not used previously
when splitting in dcn3.
Signed-off-by: Dmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Reviewed-by: Eric Bernstein <eric.bernstein@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn30/dcn30_resource.c

@@ -1899,6 +1899,41 @@ static bool dcn30_split_stream_for_mpc_or_odm(
 	return true;
 }
 
+static struct pipe_ctx *dcn30_find_split_pipe(
+		struct dc *dc,
+		struct dc_state *context)
+{
+	struct pipe_ctx *pipe = NULL;
+	int i;
+
+	for (i = dc->res_pool->pipe_count - 1; i >= 0; i--) {
+		if (dc->current_state->res_ctx.pipe_ctx[i].top_pipe == NULL
+				&& dc->current_state->res_ctx.pipe_ctx[i].prev_odm_pipe == NULL) {
+			if (context->res_ctx.pipe_ctx[i].stream == NULL) {
+				pipe = &context->res_ctx.pipe_ctx[i];
+				pipe->pipe_idx = i;
+				break;
+			}
+		}
+	}
+
+	/*
+	 * May need to fix pipes getting tossed from 1 opp to another on flip
+	 * Add for debugging transient underflow during topology updates:
+	 * ASSERT(pipe);
+	 */
+	if (!pipe)
+		for (i = dc->res_pool->pipe_count - 1; i >= 0; i--) {
+			if (context->res_ctx.pipe_ctx[i].stream == NULL) {
+				pipe = &context->res_ctx.pipe_ctx[i];
+				pipe->pipe_idx = i;
+				break;
+			}
+		}
+
+	return pipe;
+}
+
 static bool dcn30_internal_validate_bw(
 		struct dc *dc,
 		struct dc_state *context,
@@ -2024,6 +2059,7 @@ static bool dcn30_internal_validate_bw(
 				dcn20_release_dsc(&context->res_ctx, dc->res_pool, &pipe->stream_res.dsc);
 			memset(&pipe->plane_res, 0, sizeof(pipe->plane_res));
 			memset(&pipe->stream_res, 0, sizeof(pipe->stream_res));
+			repopulate_pipes = true;
 		} else if (pipe->top_pipe && pipe->top_pipe->plane_state == pipe->plane_state) {
 			struct pipe_ctx *top_pipe = pipe->top_pipe;
 			struct pipe_ctx *bottom_pipe = pipe->bottom_pipe;
@@ -2038,6 +2074,7 @@ static bool dcn30_internal_validate_bw(
 			pipe->stream = NULL;
 			memset(&pipe->plane_res, 0, sizeof(pipe->plane_res));
 			memset(&pipe->stream_res, 0, sizeof(pipe->stream_res));
+			repopulate_pipes = true;
 		} else
 			ASSERT(0); /* Should never try to merge master pipe */
 
@@ -2058,7 +2095,7 @@ static bool dcn30_internal_validate_bw(
 			continue;
 
 		if (split[i]) {
-			hsplit_pipe = find_idle_secondary_pipe(&context->res_ctx, dc->res_pool, pipe);
+			hsplit_pipe = dcn30_find_split_pipe(dc, context);
 			ASSERT(hsplit_pipe);
 			if (!hsplit_pipe)
 				goto validate_fail;
@@ -2072,7 +2109,7 @@ static bool dcn30_internal_validate_bw(
 			repopulate_pipes = true;
 		}
 		if (split[i] == 4) {
-			struct pipe_ctx *pipe_4to1 = find_idle_secondary_pipe(&context->res_ctx, dc->res_pool, pipe);
+			struct pipe_ctx *pipe_4to1 = dcn30_find_split_pipe(dc, context);
 
 			ASSERT(pipe_4to1);
 			if (!pipe_4to1)
@@ -2083,7 +2120,7 @@ static bool dcn30_internal_validate_bw(
 				goto validate_fail;
 			newly_split[pipe_4to1->pipe_idx] = true;
 
-			pipe_4to1 = find_idle_secondary_pipe(&context->res_ctx, dc->res_pool, pipe);
+			pipe_4to1 = dcn30_find_split_pipe(dc, context);
 			ASSERT(pipe_4to1);
 			if (!pipe_4to1)
 				goto validate_fail;