drm/amd/display: Clear encoder assignments when state cleared.

[Why]
State can be cleared without removing individual streams (by
calling dc_remove_stream_from_ctx()). This can leave the
encoder assignment module in an incoherent state and cause
future assignments to be incorrect.

[How]
Clear encoder assignments when committing 0 streams or
re-initializing hardware.

Acked-by: Aurabindo Pillai <[e-mail]>
Signed-off-by: Jimmy Kizito <[e-mail]>
Reviewed-by: Jun Lei <[e-mail]>
Tested-by: Daniel Wheeler <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

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

···
 
 	return link_enc;
 }
+/* Clear all link encoder assignments. */
+static void clear_enc_assignments(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;
+	}
+}
 
 void link_enc_cfg_init(
 		struct dc *dc,
···
 		else
 			state->res_ctx.link_enc_cfg_ctx.link_enc_avail[i] = ENGINE_ID_UNKNOWN;
 	}
+
+	clear_enc_assignments(state);
 
 	state->res_ctx.link_enc_cfg_ctx.mode = LINK_ENC_CFG_STEADY;
 }
···
 	int j;
 
 	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++)