Commit dad7d84f authored by Lyude Paul's avatar Lyude Paul
Browse files

drm/dp_mst: Don't forget to update port->input in drm_dp_mst_handle_conn_stat() 



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 <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>
Reviewed-by: default avatarSean Paul <sean@poorly.run>
Signed-off-by: default avatarLyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191022023641.8026-8-lyude@redhat.com
parent 3f9b3f02

drivers/gpu/drm/drm_dp_mst_topology.c

+36 −14
Original line number Diff line number Diff line
@@ -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;



	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 */

	if (port->connector)

		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;
@@ -2103,9 +2123,9 @@ 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);

	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) {
@@ -2113,11 +2133,13 @@ drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb, 
			  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);

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