From dad7d84f883571dddb686c426cfd2533f58e7c27 Mon Sep 17 00:00:00 2001 From: Lyude Paul Date: Wed, 16 Oct 2019 17:50:15 -0400 Subject: [PATCH] drm/dp_mst: Don't forget to update port->input in drm_dp_mst_handle_conn_stat() MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit This probably hasn't caused any problems up until now since it's probably nearly impossible to encounter this in the wild, however if we were to receive a connection status notification from the MST hub after resume while we're in the middle of reprobing the link addresses for a topology then there's a much larger chance that a port could have changed from being an output port to input port (or vice versa). If we forget to update this bit of information, we'll potentially ignore a valid PDT change on a downstream port because we think it's an input port. So, make sure we read the input_port field in connection status notifications in drm_dp_mst_handle_conn_stat() to prevent this from happening once we've implemented suspend/resume reprobing. Cc: Juston Li Cc: Imre Deak Cc: Ville Syrjälä Cc: Harry Wentland Cc: Daniel Vetter Reviewed-by: Sean Paul Signed-off-by: Lyude Paul Link: https://patchwork.freedesktop.org/patch/msgid/20191022023641.8026-8-lyude@redhat.com --- drivers/gpu/drm/drm_dp_mst_topology.c | 50 +++++++++++++++++++-------- 1 file changed, 36 insertions(+), 14 deletions(-) diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index 55f289eebea7e..5e031b0ca7267 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -2079,18 +2079,38 @@ drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb, { struct drm_dp_mst_topology_mgr *mgr = mstb->mgr; struct drm_dp_mst_port *port; - int old_ddps; - bool dowork = false; + int old_ddps, ret; + u8 new_pdt; + bool dowork = false, create_connector = false; port = drm_dp_get_port(mstb, conn_stat->port_number); if (!port) return; - /* Locking is only needed if the port's exposed to userspace */ - if (port->connector) + if (port->connector) { + if (!port->input && conn_stat->input_port) { + /* + * We can't remove a connector from an already exposed + * port, so just throw the port out and make sure we + * reprobe the link address of it's parent MSTB + */ + drm_dp_mst_topology_unlink_port(mgr, port); + mstb->link_address_sent = false; + dowork = true; + goto out; + } + + /* Locking is only needed if the port's exposed to userspace */ drm_modeset_lock(&mgr->base.lock, NULL); + } else if (port->input && !conn_stat->input_port) { + create_connector = true; + /* Reprobe link address so we get num_sdp_streams */ + mstb->link_address_sent = false; + dowork = true; + } old_ddps = port->ddps; + port->input = conn_stat->input_port; port->mcs = conn_stat->message_capability_status; port->ldps = conn_stat->legacy_device_plug_status; port->ddps = conn_stat->displayport_device_plug_status; @@ -2103,21 +2123,23 @@ drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb, } } - if (!port->input) { - int ret = drm_dp_port_set_pdt(port, - conn_stat->peer_device_type); - if (ret == 1) { - dowork = true; - } else if (ret < 0) { - DRM_ERROR("Failed to change PDT for port %p: %d\n", - port, ret); - dowork = false; - } + new_pdt = port->input ? DP_PEER_DEVICE_NONE : conn_stat->peer_device_type; + + ret = drm_dp_port_set_pdt(port, new_pdt); + if (ret == 1) { + dowork = true; + } else if (ret < 0) { + DRM_ERROR("Failed to change PDT for port %p: %d\n", + port, ret); + dowork = false; } if (port->connector) drm_modeset_unlock(&mgr->base.lock); + else if (create_connector) + drm_dp_mst_port_add_connector(mstb, port); +out: drm_dp_mst_topology_put_port(port); if (dowork) queue_work(system_long_wq, &mstb->mgr->work); -- 2.30.2