From: Wenjing Liu <Wenjing.Liu@amd.com>
Date: Thu, 21 Sep 2017 18:53:40 -0400
Subject: drm/amd/display: update link type to mst before topology discovery
Git-commit: e4ba6335cd91367f31978db1fc62d6bac0489672
Patch-mainline: v4.15-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

[Description]
link type is not updated before mst topology discovery.
This causes issue when branch device response to link address after before
the start topology discovery event finishes.

[Solution]
update link type to mst before topology discovery

Signed-off-by: Wenjing Liu <Wenjing.Liu@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/amd/display/dc/core/dc_link.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
@@ -496,6 +496,7 @@ static void detect_dp(
 		}
 		if (is_mst_supported(link)) {
 			sink_caps->signal = SIGNAL_TYPE_DISPLAY_PORT_MST;
+			link->type = dc_connection_mst_branch;
 
 			/*
 			 * This call will initiate MST topology discovery. Which
@@ -524,12 +525,11 @@ static void detect_dp(
 			if (reason == DETECT_REASON_BOOT)
 				boot = true;
 
-			if (dm_helpers_dp_mst_start_top_mgr(
+			if (!dm_helpers_dp_mst_start_top_mgr(
 				link->ctx,
 				link, boot)) {
-				link->type = dc_connection_mst_branch;
-			} else {
 				/* MST not supported */
+				link->type = dc_connection_single;
 				sink_caps->signal = SIGNAL_TYPE_DISPLAY_PORT;
 			}
 		}