[PATCH 05/13] dc: do blocked MST topology discovery at resume from S3/S4

[Jasdeep Dhillon]

From: "Guo, Bing" <Bing.Guo at amd.com>

Why:
When resume from sleep or hiberation, blocked MST Topology discovery might
need to be used.

How:
Added "DETECT_REASON_RESUMEFROMS3S4" to enum dc_detect_reason; use it to
require blocked MST Topology discovery.

Reviewed-by: Wenjing Liu <Wenjing.Liu at amd.com>
Acked-by: Jasdeep Dhillon <jdhillon at amd.com>
Signed-off-by: "Bing Guo" <Bing.Guo at amd.com>
---
 drivers/gpu/drm/amd/display/dc/core/dc_link.c | 2 +-
 drivers/gpu/drm/amd/display/dc/dc_link.h      | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link.c b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
index cb6c91cd6e83..ec4b300ec067 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
@@ -831,7 +831,7 @@ static bool discover_dp_mst_topology(struct dc_link *link, enum dc_detect_reason
 	link->type = dc_connection_mst_branch;
 	dm_helpers_dp_update_branch_info(link->ctx, link);
 	if (dm_helpers_dp_mst_start_top_mgr(link->ctx,
-			link, reason == DETECT_REASON_BOOT)) {
+			link, (reason == DETECT_REASON_BOOT || reason == DETECT_REASON_RESUMEFROMS3S4))) {
 		link_disconnect_sink(link);
 	} else {
 		link->type = dc_connection_sst_branch;
diff --git a/drivers/gpu/drm/amd/display/dc/dc_link.h b/drivers/gpu/drm/amd/display/dc/dc_link.h
index e7ead9e25318..9ad3ee4079c3 100644
--- a/drivers/gpu/drm/amd/display/dc/dc_link.h
+++ b/drivers/gpu/drm/amd/display/dc/dc_link.h
@@ -312,6 +312,7 @@ void dc_link_blank_dp_stream(struct dc_link *link, bool hw_init);
  */
 enum dc_detect_reason {
 	DETECT_REASON_BOOT,
+	DETECT_REASON_RESUMEFROMS3S4,
 	DETECT_REASON_HPD,
 	DETECT_REASON_HPDRX,
 	DETECT_REASON_FALLBACK,
-- 
2.25.1