[PATCH] usb: acpi: fix boot hang due to early incorrect 'tunneled' USB3 device links

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

Fix a boot hang issue triggered when a USB3 device is incorrectly assumed
to be tunneled over USB4, thus attempting to create a device link between
the USB3 "consumer" device and the USB4 "supplier" Host Interface before
the USB4 side is properly bound to a driver.

This could happen if xhci isn't capable of detecting tunneled devices,
but ACPI tables contain all info needed to assume device is tunneled.
i.e. udev->tunnel_mode == USB_LINK_UNKNOWN.

If the USB4 host interface hasn't probed yet, then we know the USB3
device is not in a tunnel created by the USB4 Host Interface driver, so
don't try to create a device link in this case.

cc: Mario Limonciello <mario.limonciello@amd.com>
Fixes: f1bfb4a6fed6 ("usb: acpi: add device link between tunneled USB3 device and USB4 Host Interface")
Tested-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
---
 drivers/usb/core/usb-acpi.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/usb/core/usb-acpi.c b/drivers/usb/core/usb-acpi.c
index 21585ed89ef8..9e1ec71881db 100644
--- a/drivers/usb/core/usb-acpi.c
+++ b/drivers/usb/core/usb-acpi.c
@@ -173,6 +173,17 @@ static int usb_acpi_add_usb4_devlink(struct usb_device *udev)
 	if (IS_ERR(nhi_fwnode))
 		return 0;
 
+	/*
+	 * If USB4 Host interface driver isn't set up yet we can't be in a USB3
+	 * tunnel created by it.
+	 */
+	if (!nhi_fwnode->dev || !device_is_bound(nhi_fwnode->dev)) {
+		dev_info(&port_dev->dev, "%s probed before USB4 host interface\n",
+			 dev_name(&port_dev->child->dev));
+		udev->tunnel_mode = USB_LINK_NATIVE;
+		return 0;
+	}
+
 	link = device_link_add(&port_dev->child->dev, nhi_fwnode->dev,
 			       DL_FLAG_AUTOREMOVE_CONSUMER |
 			       DL_FLAG_RPM_ACTIVE |
-- 
2.25.1