xhci: fix runtime PM imbalance in USB2 resume

A race between system resume and device-initiated resume may result in
runtime PM imbalance on USB2 root hub. If a device-initiated resume
starts and system resume xhci_bus_resume() directs U0 before hub driver
sees the resuming device in RESUME state, device-initiated resume will
not be finished in xhci_handle_usb2_port_link_resume(). In this case,
usb_hcd_end_port_resume() call is missing.

This changes calls usb_hcd_end_port_resume() if resuming device reaches
U0 to keep runtime PM balance.

Fixes: a231ec41e6f6 ("xhci: refactor U0 link state handling in get_port_status")
Cc: stable@vger.kernel.org
Signed-off-by: Henry Lin <henryl@nvidia.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20220303110903.1662404-5-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index bb4f01c..1e7dc13 100644 (file)
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -1088,6 +1088,9 @@ static void xhci_get_usb2_port_status(struct xhci_port *port, u32 *status,
                if (link_state == XDEV_U2)
                        *status |= USB_PORT_STAT_L1;
                if (link_state == XDEV_U0) {
+                       if (bus_state->resume_done[portnum])
+                               usb_hcd_end_port_resume(&port->rhub->hcd->self,
+                                                       portnum);
                        bus_state->resume_done[portnum] = 0;
                        clear_bit(portnum, &bus_state->resuming_ports);
                        if (bus_state->suspended_ports & (1 << portnum)) {