[RFT PATCH] xhci: track port suspend state correctly in unsuccessful resume cases

[Mathias Nyman <mathias.nyman@linux.intel.com>]

xhci-hub.c tracks suspended ports in a suspended_port bitfield.
This is checked when responding to a Get_Status(PORT) request to see if a
port in running U0 state was recently resumed, and adds the required
USB_PORT_STAT_C_SUSPEND change bit in those cases.

The suspended_port bit was left uncleared if a device is disconnected
during suspend. The bit remained set even when a new device was connected
and enumerated. The set bit resulted in a incorrect Get_Status(PORT)
response with a bogus USB_PORT_STAT_C_SUSPEND change
bit set once the new device reached U0 link state.

USB_PORT_STAT_C_SUSPEND change bit is only used for USB2 ports, but
xhci-hub keeps track of both USB2 and USB3 suspended ports.

Reported-by: Wesley Cheng <quic_wcheng@quicinc.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
---
 drivers/usb/host/xhci-hub.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index 0054d02239e2..0df5d807a77e 100644
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -1062,19 +1062,19 @@ static void xhci_get_usb3_port_status(struct xhci_port *port, u32 *status,
 		*status |= USB_PORT_STAT_C_CONFIG_ERROR << 16;
 
 	/* USB3 specific wPortStatus bits */
-	if (portsc & PORT_POWER) {
+	if (portsc & PORT_POWER)
 		*status |= USB_SS_PORT_STAT_POWER;
-		/* link state handling */
-		if (link_state == XDEV_U0)
-			bus_state->suspended_ports &= ~(1 << portnum);
-	}
 
-	/* remote wake resume signaling complete */
-	if (bus_state->port_remote_wakeup & (1 << portnum) &&
+	/* no longer suspended or resuming */
+	if (link_state != XDEV_U3 &&
 	    link_state != XDEV_RESUME &&
 	    link_state != XDEV_RECOVERY) {
-		bus_state->port_remote_wakeup &= ~(1 << portnum);
-		usb_hcd_end_port_resume(&hcd->self, portnum);
+		/* remote wake resume signaling complete */
+		if (bus_state->port_remote_wakeup & (1 << portnum)) {
+			bus_state->port_remote_wakeup &= ~(1 << portnum);
+			usb_hcd_end_port_resume(&hcd->self, portnum);
+		}
+		bus_state->suspended_ports &= ~(1 << portnum);
 	}
 
 	xhci_hub_report_usb3_link_state(xhci, status, portsc);
@@ -1131,6 +1131,7 @@ static void xhci_get_usb2_port_status(struct xhci_port *port, u32 *status,
 			usb_hcd_end_port_resume(&port->rhub->hcd->self, portnum);
 		}
 		port->rexit_active = 0;
+		bus_state->suspended_ports &= ~(1 << portnum);
 	}
 }
 
-- 
2.25.1