[J] [PATCH 1/2] xhci: stop polling roothubs after shutdown

Kai-Heng Feng kai.heng.feng at canonical.com
Wed Jun 1 13:02:22 UTC 2022

From: Henry Lin <henryl at nvidia.com>

BugLink: https://bugs.launchpad.net/bugs/1976503

While rebooting, XHCI controller and its bus device will be shut down
in order by .shutdown callback. Stopping roothubs polling in
xhci_shutdown() can prevent XHCI driver from accessing port status
after its bus device shutdown.

Take PCIe XHCI controller as example, if XHCI driver doesn't stop roothubs
polling, XHCI driver may access PCIe BAR register for port status after
parent PCIe root port driver is shutdown and cause PCIe bus error.

[check shared hcd exist before stopping its roothub polling -Mathias]

Cc: stable at vger.kernel.org
Signed-off-by: Henry Lin <henryl at nvidia.com>
Signed-off-by: Mathias Nyman <mathias.nyman at linux.intel.com>
Link: https://lore.kernel.org/r/20220408134823.2527272-3-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
(cherry picked from commit dc92944a014cd6a6f6c94299aaa36164dd2c238a)
Signed-off-by: Kai-Heng Feng <kai.heng.feng at canonical.com>
 drivers/usb/host/xhci.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 2c1cc94808875..90f5a3ce7c348 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -778,6 +778,17 @@ void xhci_shutdown(struct usb_hcd *hcd)
 	if (xhci->quirks & XHCI_SPURIOUS_REBOOT)
+	/* Don't poll the roothubs after shutdown. */
+	xhci_dbg(xhci, "%s: stopping usb%d port polling.\n",
+			__func__, hcd->self.busnum);
+	clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);
+	del_timer_sync(&hcd->rh_timer);
+	if (xhci->shared_hcd) {
+		clear_bit(HCD_FLAG_POLL_RH, &xhci->shared_hcd->flags);
+		del_timer_sync(&xhci->shared_hcd->rh_timer);
+	}
 	/* Workaround for spurious wakeups at shutdown with HSW */

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