drm/amd/display: fix stale info in link encoder assignment

[Why]
The link encoder assignment leaves the old stream data when it was
unassigned. When the clear encoder assignment is called, it based on the
old stale data to access the de-allocated stream.

[How]
There should be no need to explicitly clean up the link encoder
assignment if the unassign loop does the work properly, the loop should
base on the current state to clean up the assignment.

Also, the unassignment should better clean up the values in the
assignement slots as well.
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Anson Jacob <Anson.Jacob@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Roy Chan <roy.chan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -118,7 +118,10 @@ static void remove_link_enc_assignment(
 				 */
 				if (get_stream_using_link_enc(state, eng_id) == NULL)
 					state->res_ctx.link_enc_cfg_ctx.link_enc_avail[eng_idx] = eng_id;
+
 				stream->link_enc = NULL;
+				state->res_ctx.link_enc_cfg_ctx.link_enc_assignments[i].eng_id = ENGINE_ID_UNKNOWN;
+				state->res_ctx.link_enc_cfg_ctx.link_enc_assignments[i].stream = NULL;
 				break;
 			}
 		}
@@ -237,28 +240,15 @@ static struct link_encoder *get_link_enc_used_by_link(
 	return link_enc;
 }
 /* Clear all link encoder assignments. */
-static void clear_enc_assignments(struct dc_state *state)
+static void clear_enc_assignments(struct dc *dc, struct dc_state *state)
 {
 	int i;
-	enum engine_id eng_id;
-	struct dc_stream_state *stream;
 
 	for (i = 0; i < MAX_PIPES; i++) {
 		state->res_ctx.link_enc_cfg_ctx.link_enc_assignments[i].valid = false;
-		eng_id = state->res_ctx.link_enc_cfg_ctx.link_enc_assignments[i].eng_id;
-		stream = state->res_ctx.link_enc_cfg_ctx.link_enc_assignments[i].stream;
-		if (eng_id != ENGINE_ID_UNKNOWN)
-			state->res_ctx.link_enc_cfg_ctx.link_enc_avail[eng_id - ENGINE_ID_DIGA] = eng_id;
-		if (stream)
-			stream->link_enc = NULL;
+		state->res_ctx.link_enc_cfg_ctx.link_enc_assignments[i].eng_id = ENGINE_ID_UNKNOWN;
+		state->res_ctx.link_enc_cfg_ctx.link_enc_assignments[i].stream = NULL;
 	}
-}
-
-void link_enc_cfg_init(
-		struct dc *dc,
-		struct dc_state *state)
-{
-	int i;
 
 	for (i = 0; i < dc->res_pool->res_cap->num_dig_link_enc; i++) {
 		if (dc->res_pool->link_encoders[i])
@@ -266,8 +256,13 @@ void link_enc_cfg_init(
 		else
 			state->res_ctx.link_enc_cfg_ctx.link_enc_avail[i] = ENGINE_ID_UNKNOWN;
 	}
+}
 
-	clear_enc_assignments(state);
+void link_enc_cfg_init(
+		struct dc *dc,
+		struct dc_state *state)
+{
+	clear_enc_assignments(dc, state);
 
 	state->res_ctx.link_enc_cfg_ctx.mode = LINK_ENC_CFG_STEADY;
 }
@@ -284,12 +279,9 @@ void link_enc_cfg_link_encs_assign(
 
 	ASSERT(state->stream_count == stream_count);
 
-	if (stream_count == 0)
-		clear_enc_assignments(state);
-
 	/* Release DIG link encoder resources before running assignment algorithm. */
-	for (i = 0; i < stream_count; i++)
-		dc->res_pool->funcs->link_enc_unassign(state, streams[i]);
+	for (i = 0; i < dc->current_state->stream_count; i++)
+		dc->res_pool->funcs->link_enc_unassign(state, dc->current_state->streams[i]);
 
 	for (i = 0; i < MAX_PIPES; i++)
 		ASSERT(state->res_ctx.link_enc_cfg_ctx.link_enc_assignments[i].valid == false);