[PATCH 08/18] drm/amd/display: Have Payload Properly Created After Resume

[Tom Chung]

From: Fangzhi Zuo <jerry.zuo at amd.com>

At drm suspend sequence, MST dc_sink is removed. When commit cached
MST stream back in drm resume sequence, the MST stream payload is not
properly created and added into the payload table. After resume, topology
change is reprobed by removing existing streams first. That leads to
no payload is found in the existing payload table as below error
"[drm] ERROR No payload for [MST PORT:] found in mst state"

1. In encoder .atomic_check routine, remove check existance of dc_sink
2. Bypass MST by checking existence of MST root port. dc_link_type cannot
differentiate MST port before topology is rediscovered.

Reviewed-by: Wayne Lin <wayne.lin at amd.com>
Acked-by: Tom Chung <chiahsuan.chung at amd.com>
Signed-off-by: Fangzhi Zuo <jerry.zuo at amd.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index b8e0fc189002..5d34fd0ca777 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -2852,7 +2852,7 @@ static int dm_resume(void *handle)
 		 * this is the case when traversing through already created
 		 * MST connectors, should be skipped
 		 */
-		if (aconnector->dc_link->type == dc_connection_mst_branch)
+		if (aconnector && aconnector->mst_root)
 			continue;
 
 		mutex_lock(&aconnector->hpd_lock);
@@ -6776,7 +6776,7 @@ static int dm_encoder_helper_atomic_check(struct drm_encoder *encoder,
 	int clock, bpp = 0;
 	bool is_y420 = false;
 
-	if (!aconnector->mst_output_port || !aconnector->dc_sink)
+	if (!aconnector->mst_output_port)
 		return 0;
 
 	mst_port = aconnector->mst_output_port;
-- 
2.25.1