drm/amd/display: Determine synchronization edge based on master's vsync

[Why&How]
The driver always wants to synchronize streams
to the first edge of master's vsync pulse.
In order to determine that we can read timing
flags that are used to program vsync.

Master stream's vsync polarity - Multi Display Stream Synchronization edge:

        Negative               -              Falling Edge

        Positive               -              Rising Edge
Signed-off-by: Mikita Lipski <mikita.lipski@amd.com>
Reviewed-by: Sun peng Li <Sunpeng.Li@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -5320,9 +5320,14 @@ create_fake_sink(struct amdgpu_dm_connector *aconnector)
 static void set_multisync_trigger_params(
 		struct dc_stream_state *stream)
 {
+	struct dc_stream_state *master = NULL;
+
 	if (stream->triggered_crtc_reset.enabled) {
-		stream->triggered_crtc_reset.event = CRTC_EVENT_VSYNC_RISING;
-		stream->triggered_crtc_reset.delay = TRIGGER_DELAY_NEXT_LINE;
+		master = stream->triggered_crtc_reset.event_source;
+		stream->triggered_crtc_reset.event =
+			master->timing.flags.VSYNC_POSITIVE_POLARITY ?
+			CRTC_EVENT_VSYNC_RISING : CRTC_EVENT_VSYNC_FALLING;
+		stream->triggered_crtc_reset.delay = TRIGGER_DELAY_NEXT_PIXEL;
 	}
 }
 
@@ -5352,6 +5357,7 @@ static void set_master_stream(struct dc_stream_state *stream_set[],
 static void dm_enable_per_frame_crtc_master_sync(struct dc_state *context)
 {
 	int i = 0;
+	struct dc_stream_state *stream;
 
 	if (context->stream_count < 2)
 		return;
@@ -5363,9 +5369,18 @@ static void dm_enable_per_frame_crtc_master_sync(struct dc_state *context)
 		 * crtc_sync_master.multi_sync_enabled flag
 		 * For now it's set to false
 		 */
-		set_multisync_trigger_params(context->streams[i]);
 	}
+
 	set_master_stream(context->streams, context->stream_count);
+
+	for (i = 0; i < context->stream_count ; i++) {
+		stream = context->streams[i];
+
+		if (!stream)
+			continue;
+
+		set_multisync_trigger_params(stream);
+	}
 }
 
 static struct drm_display_mode *