[PATCH] drm/amd/display: Fix missing unlock in dm_handle_mst_sideband_msg_ready_event()

[Yang Yingliang]

Add missing mutex_unlock() in error path in
dm_handle_mst_sideband_msg_ready_event().

Fixes: 4f6d9e38c4d2 ("drm/amd/display: Add polling method to handle MST reply 
packet")
Signed-off-by: Yang Yingliang <yangyingli...@huawei.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c | 1 +
 1 file changed, 1 insertion(+)

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 1abdec14344e..cddb91cf3dde 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
@@ -707,6 +707,7 @@ void dm_handle_mst_sideband_msg_ready_event(
 
                        if (retry == 3) {
                                DRM_ERROR("Failed to ack MST event.\n");
+                               mutex_unlock(&aconnector->handle_mst_msg_ready);
                                return;
                        }
 
-- 
2.25.1