thunderbolt: Do not call PM runtime functions in tb_retimer_scan()

We cannot call PM runtime functions in tb_retimer_scan() because it will
also be called when retimers are scanned from userspace (happens when
there is no device connected on ChromeOS for instance) and at the same
USB4 port runtime resume hook. This leads to hang because neither can
proceed.

Fix this by runtime resuming USB4 ports in tb_scan_port() instead. This
makes sure the ports are runtime PM active when retimers are added under
it while avoiding the reported hang as well.

Reported-by: Utkarsh Patel <utkarsh.h.patel@intel.com>
Fixes: 1e56c88adecc ("thunderbolt: Runtime resume USB4 port when retimers are scanned")
Cc: stable@vger.kernel.org
Acked-by: Yehezkel Bernat <YehezkelShB@gmail.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

1 files changed, 15 insertions, 5 deletions

diff --git a/drivers/thunderbolt/tb.c b/drivers/thunderbolt/tb.c
index 462845804427..3f1ab30c4fb1 100644
--- a/drivers/thunderbolt/tb.c
+++ b/drivers/thunderbolt/tb.c
@@ -628,11 +628,15 @@ static void tb_scan_port(struct tb_port *port)
 			 * Downstream switch is reachable through two ports.
 			 * Only scan on the primary port (link_nr == 0).
 			 */
+
+	if (port->usb4)
+		pm_runtime_get_sync(&port->usb4->dev);
+
 	if (tb_wait_for_port(port, false) <= 0)
-		return;
+		goto out_rpm_put;
 	if (port->remote) {
 		tb_port_dbg(port, "port already has a remote\n");
-		return;
+		goto out_rpm_put;
 	}
 
 	tb_retimer_scan(port, true);
@@ -647,12 +651,12 @@ static void tb_scan_port(struct tb_port *port)
 		 */
 		if (PTR_ERR(sw) == -EIO || PTR_ERR(sw) == -EADDRNOTAVAIL)
 			tb_scan_xdomain(port);
-		return;
+		goto out_rpm_put;
 	}
 
 	if (tb_switch_configure(sw)) {
 		tb_switch_put(sw);
-		return;
+		goto out_rpm_put;
 	}
 
 	/*
@@ -681,7 +685,7 @@ static void tb_scan_port(struct tb_port *port)
 
 	if (tb_switch_add(sw)) {
 		tb_switch_put(sw);
-		return;
+		goto out_rpm_put;
 	}
 
 	/* Link the switches using both links if available */
@@ -733,6 +737,12 @@ static void tb_scan_port(struct tb_port *port)
 
 	tb_add_dp_resources(sw);
 	tb_scan_switch(sw);
+
+out_rpm_put:
+	if (port->usb4) {
+		pm_runtime_mark_last_busy(&port->usb4->dev);
+		pm_runtime_put_autosuspend(&port->usb4->dev);
+	}
 }
 
 static void tb_deactivate_and_free_tunnel(struct tb_tunnel *tunnel)