From: Henry Lin henryl@nvidia.com

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 --- drivers/usb/host/xhci-hub.c | 3 +++ 1 file changed, 3 insertions(+)

diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c index bb4f01ce90e3..1e7dc130c39a 100644 --- 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)) {