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Commit a1ff718d authored by Fuad Hossain's avatar Fuad Hossain
Browse files

drm: Read dp mst edid immediately after plugin 



In the current implementation, if a new dp
connector is plugged in to an existing port, the
edid is not read during plugin time. The edid is
read when userspace calls get_connector(), while
kernel is holding the atomic modeset lock. Since
the get_edid call may take a couple of seconds,
no frames can be committed during this time,
which causes a momentary freeze.

Fix this issue by reading and caching the edid as
soon as the connector is plugged in. This will
prevent the atomic commit from blocking,
resulting in no freeze upon plugin.

CRs-Fixed: 2496461
Change-Id: I9414ce072c8e6e4919c15291331e9e08b9030460
Signed-off-by: default avatarFuad Hossain <fhossain@codeaurora.org>
parent 28ad72b2

drivers/gpu/drm/drm_dp_mst_topology.c

+47 −2
Original line number Diff line number Diff line
@@ -1176,6 +1176,14 @@ static void drm_dp_add_port(struct drm_dp_mst_branch *mstb, 
		port->aux.dev = dev->dev;

		created = true;

	} else {

		if (port->pdt == DP_PEER_DEVICE_DP_LEGACY_CONV ||

				port->pdt == DP_PEER_DEVICE_SST_SINK) {

			if (!port->cached_edid)

				port->cached_edid = drm_get_edid(

						port->connector,

						&port->aux.ddc);

		}



		old_pdt = port->pdt;

		old_ddps = port->ddps;

	}
@@ -1249,6 +1257,7 @@ static void drm_dp_update_port(struct drm_dp_mst_branch *mstb, 
	int old_pdt;

	int old_ddps;

	bool dowork = false;

	bool dohotplug = false;

	port = drm_dp_get_port(mstb, conn_stat->port_number);

	if (!port)

		return;
@@ -1273,6 +1282,7 @@ static void drm_dp_update_port(struct drm_dp_mst_branch *mstb, 
		    port->port_num < DP_MST_LOGICAL_PORT_0) {

			kfree(port->cached_edid);

			port->cached_edid = NULL;

			dohotplug = true;

		}



		drm_dp_port_teardown_pdt(port, old_pdt);
@@ -1285,6 +1295,8 @@ static void drm_dp_update_port(struct drm_dp_mst_branch *mstb, 
	if (dowork)

		queue_work(system_long_wq, &mstb->mgr->work);



	if (dohotplug)

		(*mstb->mgr->cbs->hotplug)(mstb->mgr);

}



static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct drm_dp_mst_topology_mgr *mgr,
@@ -1365,6 +1377,40 @@ static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device_by_guid( 
	return mstb;

}



static void drm_dp_reset_sink_mstb_link_address_sent(

		struct drm_dp_mst_topology_mgr *mgr,

		struct drm_dp_mst_branch *mstb)

{

	struct drm_dp_mst_port *port;

	struct drm_dp_mst_branch *mstb_child;

	struct drm_dp_mst_branch *mstb_parent;



	list_for_each_entry(port, &mstb->ports, next) {

		if (port->input)

			continue;



		if (!port->ddps)

			continue;



		if (port->mstb) {

			mstb_child = drm_dp_get_validated_mstb_ref(mgr,

					port->mstb);

			if (mstb_child) {

				drm_dp_reset_sink_mstb_link_address_sent(mgr,

						mstb_child);

				drm_dp_put_mst_branch_device(mstb_child);

			}

		} else {

			mstb_parent = drm_dp_get_validated_mstb_ref(mgr,

					port->parent);

			if (mstb_parent) {

				mstb_parent->link_address_sent = false;

				drm_dp_put_mst_branch_device(mstb_parent);

			}

		}

	}

}



static void drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *mgr,

					       struct drm_dp_mst_branch *mstb)

{
@@ -1405,6 +1451,7 @@ static void drm_dp_mst_link_probe_work(struct work_struct *work) 
	}

	mutex_unlock(&mgr->lock);

	if (mstb) {

		drm_dp_reset_sink_mstb_link_address_sent(mgr, mstb);

		drm_dp_check_and_send_link_address(mgr, mstb);

		drm_dp_put_mst_branch_device(mstb);

	}
@@ -2568,8 +2615,6 @@ static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr) 
			drm_dp_update_port(mstb, &msg.u.conn_stat);



			DRM_DEBUG_KMS("Got CSN: pn: %d ldps:%d ddps: %d mcs: %d ip: %d pdt: %d\n", msg.u.conn_stat.port_number, msg.u.conn_stat.legacy_device_plug_status, msg.u.conn_stat.displayport_device_plug_status, msg.u.conn_stat.message_capability_status, msg.u.conn_stat.input_port, msg.u.conn_stat.peer_device_type);

			(*mgr->cbs->hotplug)(mgr);



		} else if (msg.req_type == DP_RESOURCE_STATUS_NOTIFY) {

			drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, msg.req_type, seqno, false);

			if (!mstb)