1 files changed, 50 insertions, 3 deletions

diff --git a/drivers/thunderbolt/tb.c b/drivers/thunderbolt/tb.c
index e1eb092ad..c5e4fa478 100644
--- a/drivers/thunderbolt/tb.c
+++ b/drivers/thunderbolt/tb.c
@@ -1050,6 +1050,49 @@ err_rpm_put:
 	pm_runtime_put_autosuspend(&in->sw->dev);
 }
 
+static void tb_enter_redrive(struct tb_port *port)
+{
+	struct tb_switch *sw = port->sw;
+
+	if (!(sw->quirks & QUIRK_KEEP_POWER_IN_DP_REDRIVE))
+		return;
+
+	/*
+	 * If we get hot-unplug for the DP IN port of the host router
+	 * and the DP resource is not available anymore it means there
+	 * is a monitor connected directly to the Type-C port and we are
+	 * in "redrive" mode. For this to work we cannot enter RTD3 so
+	 * we bump up the runtime PM reference count here.
+	 */
+	if (!tb_port_is_dpin(port))
+		return;
+	if (tb_route(sw))
+		return;
+	if (!tb_switch_query_dp_resource(sw, port)) {
+		port->redrive = true;
+		pm_runtime_get(&sw->dev);
+		tb_port_dbg(port, "enter redrive mode, keeping powered\n");
+	}
+}
+
+static void tb_exit_redrive(struct tb_port *port)
+{
+	struct tb_switch *sw = port->sw;
+
+	if (!(sw->quirks & QUIRK_KEEP_POWER_IN_DP_REDRIVE))
+		return;
+
+	if (!tb_port_is_dpin(port))
+		return;
+	if (tb_route(sw))
+		return;
+	if (port->redrive && tb_switch_query_dp_resource(sw, port)) {
+		port->redrive = false;
+		pm_runtime_put(&sw->dev);
+		tb_port_dbg(port, "exit redrive mode\n");
+	}
+}
+
 static void tb_dp_resource_unavailable(struct tb *tb, struct tb_port *port)
 {
 	struct tb_port *in, *out;
@@ -1066,7 +1109,10 @@ static void tb_dp_resource_unavailable(struct tb *tb, struct tb_port *port)
 	}
 
 	tunnel = tb_find_tunnel(tb, TB_TUNNEL_DP, in, out);
-	tb_deactivate_and_free_tunnel(tunnel);
+	if (tunnel)
+		tb_deactivate_and_free_tunnel(tunnel);
+	else
+		tb_enter_redrive(port);
 	list_del_init(&port->list);
 
 	/*
@@ -1092,6 +1138,7 @@ static void tb_dp_resource_available(struct tb *tb, struct tb_port *port)
 	tb_port_dbg(port, "DP %s resource available\n",
 		    tb_port_is_dpin(port) ? "IN" : "OUT");
 	list_add_tail(&port->list, &tcm->dp_resources);
+	tb_exit_redrive(port);
 
 	/* Look for suitable DP IN <-> DP OUT pairs now */
 	tb_tunnel_dp(tb);
@@ -1581,7 +1628,7 @@ static int tb_resume_noirq(struct tb *tb)
 	/* remove any pci devices the firmware might have setup */
 	tb_switch_reset(tb->root_switch);
 
-	tb_switch_resume(tb->root_switch);
+	tb_switch_resume(tb->root_switch, false);
 	tb_free_invalid_tunnels(tb);
 	tb_free_unplugged_children(tb->root_switch);
 	tb_restore_children(tb->root_switch);
@@ -1707,7 +1754,7 @@ static int tb_runtime_resume(struct tb *tb)
 	struct tb_tunnel *tunnel, *n;
 
 	mutex_lock(&tb->lock);
-	tb_switch_resume(tb->root_switch);
+	tb_switch_resume(tb->root_switch, true);
 	tb_free_invalid_tunnels(tb);
 	tb_restore_children(tb->root_switch);
 	list_for_each_entry_safe(tunnel, n, &tcm->tunnel_list, list)