drm/amd/display: Fix MST downstream display not light up regression

The fix is for the scenario: MST+SST chain together, and hook up
to the card.

Regression: Per stream validate_context build v2
Before dc_add_stream_to_ctx(), need to update/reset
stream signal type to SIGNAL_TYPE_DISPLAY_PORT_MST. Otherwise,
downstream device cannot be added to ctx due to the lack of signal
type info (SIGNAL_TYPE_NONE).
update_stream_signal() needs to be done after stream is created.

Signed-off-by: Jerry Zuo <Jerry.Zuo@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -1323,7 +1323,6 @@ bool dc_is_stream_unchanged(
 
 /* Maximum TMDS single link pixel clock 165MHz */
 #define TMDS_MAX_PIXEL_CLOCK_IN_KHZ 165000
-#define TMDS_MAX_PIXEL_CLOCK_IN_KHZ_UPMOST 297000
 
 static void update_stream_engine_usage(
 		struct resource_context *res_ctx,
@@ -1434,28 +1433,6 @@ static struct audio *find_first_free_audio(
 	return 0;
 }
 
-static void update_stream_signal(struct dc_stream_state *stream)
-{
-	if (stream->output_signal == SIGNAL_TYPE_NONE) {
-		struct dc_sink *dc_sink = stream->sink;
-
-		if (dc_sink->sink_signal == SIGNAL_TYPE_NONE)
-			stream->signal = stream->sink->link->connector_signal;
-		else
-			stream->signal = dc_sink->sink_signal;
-	} else {
-		stream->signal = stream->output_signal;
-	}
-
-	if (dc_is_dvi_signal(stream->signal)) {
-		if (stream->timing.pix_clk_khz > TMDS_MAX_PIXEL_CLOCK_IN_KHZ_UPMOST &&
-			stream->sink->sink_signal != SIGNAL_TYPE_DVI_SINGLE_LINK)
-			stream->signal = SIGNAL_TYPE_DVI_DUAL_LINK;
-		else
-			stream->signal = SIGNAL_TYPE_DVI_SINGLE_LINK;
-	}
-}
-
 bool resource_is_stream_unchanged(
 	struct validate_context *old_context, struct dc_stream_state *stream)
 {
@@ -1627,8 +1604,6 @@ static int get_norm_pix_clk(const struct dc_crtc_timing *timing)
 
 static void calculate_phy_pix_clks(struct dc_stream_state *stream)
 {
-	update_stream_signal(stream);
-
 	/* update actual pixel clock on all streams */
 	if (dc_is_hdmi_signal(stream->signal))
 		stream->phy_pix_clk = get_norm_pix_clk(

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

@@ -33,6 +33,28 @@
 /*******************************************************************************
  * Private functions
  ******************************************************************************/
+#define TMDS_MAX_PIXEL_CLOCK_IN_KHZ_UPMOST 297000
+static void update_stream_signal(struct dc_stream_state *stream)
+{
+	if (stream->output_signal == SIGNAL_TYPE_NONE) {
+		struct dc_sink *dc_sink = stream->sink;
+
+		if (dc_sink->sink_signal == SIGNAL_TYPE_NONE)
+			stream->signal = stream->sink->link->connector_signal;
+		else
+			stream->signal = dc_sink->sink_signal;
+	} else {
+		stream->signal = stream->output_signal;
+	}
+
+	if (dc_is_dvi_signal(stream->signal)) {
+		if (stream->timing.pix_clk_khz > TMDS_MAX_PIXEL_CLOCK_IN_KHZ_UPMOST &&
+			stream->sink->sink_signal != SIGNAL_TYPE_DVI_SINGLE_LINK)
+			stream->signal = SIGNAL_TYPE_DVI_DUAL_LINK;
+		else
+			stream->signal = SIGNAL_TYPE_DVI_SINGLE_LINK;
+	}
+}
 
 static bool construct(struct dc_stream_state *stream,
 	struct dc_sink *dc_sink_data)
@@ -80,6 +102,8 @@ static bool construct(struct dc_stream_state *stream,
 	stream->timing.flags.LTE_340MCSC_SCRAMBLE = dc_sink_data->edid_caps.lte_340mcsc_scramble;
 
 	stream->status.link = stream->sink->link;
+
+	update_stream_signal(stream);
 	return true;
 }