[PATCH 5.12 354/700] drm/amd/dc: Fix a missing check bug in dm_dp_mst_detect()

[Greg Kroah-Hartman]

From: Yingjie Wang <wangyingjie55@xxxxxxx>

[ Upstream commit 655c0ed19772d92c9665ed08bdc5202acc096dda ]

In dm_dp_mst_detect(), We should check whether or not @connector
has been unregistered from userspace. If the connector is unregistered,
we should return disconnected status.

Fixes: 4562236b3bc0 ("drm/amd/dc: Add dc display driver (v2)")
Signed-off-by: Yingjie Wang <wangyingjie55@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
index 41b09ab22233..b478129a7477 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
@@ -270,6 +270,9 @@ dm_dp_mst_detect(struct drm_connector *connector,
 	struct amdgpu_dm_connector *aconnector = to_amdgpu_dm_connector(connector);
 	struct amdgpu_dm_connector *master = aconnector->mst_port;
 
+	if (drm_connector_is_unregistered(connector))
+		return connector_status_disconnected;
+
 	return drm_dp_mst_detect_port(connector, ctx, &master->mst_mgr,
 				      aconnector->port);
 }
-- 
2.30.2