From: Imre Deak <redacted>

[ Upstream commit 4b8878eefa0a3b65e2e016db49014ea66fb9fd45 ]

Caching EDIDs for physical ports prevents updating the EDID if a port
gets reconnected via a Connection Status Notification message, fix this.

Fixes: db1a07956968 ("drm/dp_mst: Handle SST-only branch device case")
Cc: Wayne Lin <redacted>
Cc: Lyude Paul <lyude@redhat.com>
Signed-off-by: Imre Deak <redacted>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210201120145.350258-2-imre.deak@intel.com
(cherry picked from commit 468091531c2e5c49f55d8c6f1d036ce997d24e13)
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/drm_dp_mst_topology.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index b11c0522a4410..405501c74e400 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c

@@ -2302,7 +2302,8 @@ drm_dp_mst_port_add_connector(struct drm_dp_mst_branch *mstb,
 	}
 
 	if (port->pdt != DP_PEER_DEVICE_NONE &&
-	    drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
+	    drm_dp_mst_is_end_device(port->pdt, port->mcs) &&
+	    port->port_num >= DP_MST_LOGICAL_PORT_0) {
 		port->cached_edid = drm_get_edid(port->connector,
 						 &port->aux.ddc);
 		drm_connector_set_tile_property(port->connector);

-- 
2.27.0