[Why] Currently, we will create connectors for all output ports no matter it's connected or not. However, in MST, we can only determine whether an output port really stands for a "connector" till it is connected and check its peer device type as an end device.
In current code, we have chance to create connectors for output ports connected with branch device and these are redundant connectors. e.g. StarTech 1-to-4 DP hub is constructed by internal 2 layer 1-to-2 branch devices. Creating connectors for such internal output ports are redundant.
[How] Put constraint on creating connector for connected end device only.
Fixes: 6f85f73821f6 ("drm/dp_mst: Add basic topology reprobing when resuming") Cc: Juston Li juston.li@intel.com Cc: Imre Deak imre.deak@intel.com Cc: Ville Syrjälä ville.syrjala@linux.intel.com Cc: Harry Wentland hwentlan@amd.com Cc: Daniel Vetter daniel.vetter@ffwll.ch Cc: Sean Paul sean@poorly.run Cc: Lyude Paul lyude@redhat.com Cc: Maarten Lankhorst maarten.lankhorst@linux.intel.com Cc: Maxime Ripard mripard@kernel.org Cc: Thomas Zimmermann tzimmermann@suse.de Cc: David Airlie airlied@linux.ie Cc: Daniel Vetter daniel@ffwll.ch Cc: Alex Deucher alexander.deucher@amd.com Cc: Nicholas Kazlauskas nicholas.kazlauskas@amd.com Cc: Rodrigo Siqueira Rodrigo.Siqueira@amd.com Cc: Aurabindo Pillai aurabindo.pillai@amd.com Cc: Eryk Brol eryk.brol@amd.com Cc: Bas Nieuwenhuizen bas@basnieuwenhuizen.nl Cc: Nikola Cornij nikola.cornij@amd.com Cc: Wayne Lin Wayne.Lin@amd.com Cc: "Ville Syrjälä" ville.syrjala@linux.intel.com Cc: Jani Nikula jani.nikula@intel.com Cc: Manasi Navare manasi.d.navare@intel.com Cc: Ankit Nautiyal ankit.k.nautiyal@intel.com Cc: "José Roberto de Souza" jose.souza@intel.com Cc: Sean Paul seanpaul@chromium.org Cc: Ben Skeggs bskeggs@redhat.com Cc: dri-devel@lists.freedesktop.org Cc: stable@vger.kernel.org # v5.5+ Signed-off-by: Wayne Lin Wayne.Lin@amd.com --- drivers/gpu/drm/drm_dp_mst_topology.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index 51cd7f74f026..f13c7187b07f 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -2474,7 +2474,8 @@ drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch *mstb,
if (port->connector) drm_modeset_unlock(&mgr->base.lock); - else if (!port->input) + else if (!port->input && port->pdt != DP_PEER_DEVICE_NONE && + drm_dp_mst_is_end_device(port->pdt, port->mcs)) drm_dp_mst_port_add_connector(mstb, port);
if (send_link_addr && port->mstb) { @@ -2557,6 +2558,10 @@ drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb, dowork = false; }
+ if (!port->input && !port->connector && new_pdt != DP_PEER_DEVICE_NONE && + drm_dp_mst_is_end_device(new_pdt, new_mcs)) + create_connector = true; + if (port->connector) drm_modeset_unlock(&mgr->base.lock); else if (create_connector)