[PATCH] xhci: Fix soft lockup in xhci_pci_probe path when XHCI_STATE_HALTED

[Kamal Mostafa <kamal@canonical.com>]

Commit 27a41a83ec54 ("xhci: Cleanup only when releasing primary hcd")
causes a soft lockup at boot when XHCI_STATE_HALTED, preventing
VirtualBox 5.1.x from booting if USB3.0 is enabled.

Revert to allowing xhci_irq to handle the interrupt when
XHCI_STATE_HALTED but not XHCI_STATE_DYING.

Fixes: 27a41a83ec54 ("xhci: Cleanup only when releasing primary hcd")
BugLink: https://bugs.launchpad.net/bugs/1604058
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Cc: <stable@vger.kernel.org> #v4.3+
Cc: Gabriel Krisman Bertazi <krisman@linux.vnet.ibm.com>
Acked-by: Tim Gardner <tim.gardner@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
---
 drivers/usb/host/xhci-ring.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 918e0c7..1d36a5f 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -2751,8 +2751,7 @@ hw_died:
 		writel(irq_pending, &xhci->ir_set->irq_pending);
 	}
 
-	if (xhci->xhc_state & XHCI_STATE_DYING ||
-	    xhci->xhc_state & XHCI_STATE_HALTED) {
+	if (xhci->xhc_state & XHCI_STATE_DYING) {
 		xhci_dbg(xhci, "xHCI dying, ignoring interrupt. "
 				"Shouldn't IRQs be disabled?\n");
 		/* Clear the event handler busy flag (RW1C);
@@ -2764,6 +2763,8 @@ hw_died:
 		spin_unlock(&xhci->lock);
 
 		return IRQ_HANDLED;
+	} else if (xhci->xhc_state & XHCI_STATE_HALTED) {
+		xhci_dbg(xhci, "xHCI halted, handling interrupt.\n");
 	}
 
 	event_ring_deq = xhci->event_ring->dequeue;
-- 
2.7.4