[PATCH 2/3] usb: xhci: Prevent interrupt storm on host controller error (HCE)

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

From: Dayu Jiang <jiangdayu@xiaomi.com>

The xHCI controller reports a Host Controller Error (HCE) in UAS Storage
Device plug/unplug scenarios on Android devices. HCE is checked in
xhci_irq() function and causes an interrupt storm (since the interrupt
isn’t cleared), leading to severe system-level faults.

When the xHC controller reports HCE in the interrupt handler, the driver
only logs a warning and assumes xHC activity will stop as stated in xHCI
specification. An interrupt storm does however continue on some hosts
even after HCE, and only ceases after manually disabling xHC interrupt
and stopping the controller by calling xhci_halt().

Add xhci_halt() to xhci_irq() function where STS_HCE status is checked,
mirroring the existing error handling pattern used for STS_FATAL errors.

This only fixes the interrupt storm. Proper HCE recovery requires resetting
and re-initializing the xHC.

CC: stable@vger.kernel.org
Signed-off-by: Dayu Jiang <jiangdayu@xiaomi.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
---
 drivers/usb/host/xhci-ring.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 9315ba18310d..1cbefee3c4ca 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -3195,6 +3195,7 @@ irqreturn_t xhci_irq(struct usb_hcd *hcd)
 
 	if (status & STS_HCE) {
 		xhci_warn(xhci, "WARNING: Host Controller Error\n");
+		xhci_halt(xhci);
 		goto out;
 	}
 
-- 
2.43.0