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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Mathias Nyman <mathias.nyman@linux.intel.com>
Subject: [PATCH 5.4 155/168] xhci: prevent bus suspend if a roothub port detected a over-current condition
Date:   Tue, 28 Apr 2020 20:25:29 +0200
Message-Id: <20200428182250.867738114@linuxfoundation.org>
In-Reply-To: <20200428182231.704304409@linuxfoundation.org>
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From: Mathias Nyman <mathias.nyman@linux.intel.com>

commit e9fb08d617bfae5471d902112667d0eeb9dee3c4 upstream.

Suspending the bus and host controller while a port is in a over-current
condition may halt the host.
Also keep the roothub running if over-current is active.

Cc: <stable@vger.kernel.org>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20200421140822.28233-3-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/host/xhci-hub.c |    9 +++++++++
 1 file changed, 9 insertions(+)

--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -1569,6 +1569,8 @@ int xhci_hub_status_data(struct usb_hcd
 		}
 		if ((temp & PORT_RC))
 			reset_change = true;
+		if (temp & PORT_OC)
+			status = 1;
 	}
 	if (!status && !reset_change) {
 		xhci_dbg(xhci, "%s: stopping port polling.\n", __func__);
@@ -1634,6 +1636,13 @@ retry:
 				 port_index);
 			goto retry;
 		}
+		/* bail out if port detected a over-current condition */
+		if (t1 & PORT_OC) {
+			bus_state->bus_suspended = 0;
+			spin_unlock_irqrestore(&xhci->lock, flags);
+			xhci_dbg(xhci, "Bus suspend bailout, port over-current detected\n");
+			return -EBUSY;
+		}
 		/* suspend ports in U0, or bail out for new connect changes */
 		if ((t1 & PORT_PE) && (t1 & PORT_PLS_MASK) == XDEV_U0) {
 			if ((t1 & PORT_CSC) && wake_enabled) {