[RFC PATCH] usb: xhci: report USB2 resume-exit timeout as an error

[Pengpeng Hou]

xhci_handle_usb2_port_link_resume() waits for the USB2 resume exit
completion after requesting U0. If that wait times out, it only logs a
warning and then continues through the normal resume-done path, ending
the port resume and marking the suspend change as completed.

Return -ETIMEDOUT on resume-exit timeout so the port status path reports
an error instead of a successful resume. The patch still ends the
usbcore port-resume accounting before returning. This is intended as an
RFC patch because xHCI resume state handling is policy-sensitive.

Signed-off-by: Pengpeng Hou <pengpeng@xxxxxxxxxxx>
---
 drivers/usb/host/xhci-hub.c | 32 ++++++++++++++++++--------------
 1 file changed, 18 insertions(+), 14 deletions(-)

diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index b0264bd85..b7b7d8b31 100644
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -998,21 +998,23 @@ static int xhci_handle_usb2_port_link_resume(struct xhci_port *port,
-		if (time_left) {
-			if (!port->slot_id) {
-				xhci_dbg(xhci, "slot_id is zero\n");
-				return -ENODEV;
-			}
-			xhci_ring_device(xhci, port->slot_id);
-		} else {
+		if (!time_left) {
 			int port_status = xhci_portsc_readl(port);
 
 			xhci_warn(xhci, "Port resume timed out, port %d-%d: 0x%x\n",
 				  hcd->self.busnum, wIndex + 1, port_status);
 			/*
 			 * keep rexit_active set if U0 transition failed so we
 			 * know to report PORT_STAT_SUSPEND status back to
 			 * usbcore. It will be cleared later once the port is
 			 * out of RESUME/U3 state
 			 */
+			usb_hcd_end_port_resume(&hcd->self, wIndex);
+			return -ETIMEDOUT;
 		}
 
+		if (!port->slot_id) {
+			xhci_dbg(xhci, "slot_id is zero\n");
+			return -ENODEV;
+		}
+		xhci_ring_device(xhci, port->slot_id);
+
 		usb_hcd_end_port_resume(&hcd->self, wIndex);
 		bus_state->port_c_suspend |= 1 << wIndex;
 		bus_state->suspended_ports &= ~(1 << wIndex);
-- 
2.50.1 (Apple Git-155)