thunderbolt: Tear down DP tunnels when suspending

DP tunnels do not need the same kind of treatment as others because they
are created based on hot-plug events on DP adapter ports, and the
display stack does not need the tunnels to be enabled when resuming from
suspend. Also Tiger Lake Thunderbolt controller sends unplug event on D3
exit so this avoids that as well.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

drivers/thunderbolt/tb.c

@@ -910,6 +910,29 @@ static void tb_dp_resource_available(struct tb *tb, struct tb_port *port)
 	tb_tunnel_dp(tb);
 }
 
+static void tb_disconnect_and_release_dp(struct tb *tb)
+{
+	struct tb_cm *tcm = tb_priv(tb);
+	struct tb_tunnel *tunnel, *n;
+
+	/*
+	 * Tear down all DP tunnels and release their resources. They
+	 * will be re-established after resume based on plug events.
+	 */
+	list_for_each_entry_safe_reverse(tunnel, n, &tcm->tunnel_list, list) {
+		if (tb_tunnel_is_dp(tunnel))
+			tb_deactivate_and_free_tunnel(tunnel);
+	}
+
+	while (!list_empty(&tcm->dp_resources)) {
+		struct tb_port *port;
+
+		port = list_first_entry(&tcm->dp_resources,
+					struct tb_port, list);
+		list_del_init(&port->list);
+	}
+}
+
 static int tb_tunnel_pci(struct tb *tb, struct tb_switch *sw)
 {
 	struct tb_port *up, *down, *port;
@@ -1226,6 +1249,7 @@ static int tb_suspend_noirq(struct tb *tb)
 	struct tb_cm *tcm = tb_priv(tb);
 
 	tb_dbg(tb, "suspending...\n");
+	tb_disconnect_and_release_dp(tb);
 	tb_switch_suspend(tb->root_switch);
 	tcm->hotplug_active = false; /* signal tb_handle_hotplug to quit */
 	tb_dbg(tb, "suspend finished\n");