From 623dae3e7084a9504e6dc4cf0cb83f305f413b4d Mon Sep 17 00:00:00 2001 From: Mathias Nyman Date: Thu, 24 Oct 2024 16:13:55 +0300 Subject: [PATCH] usb: acpi: fix boot hang due to early incorrect 'tunneled' USB3 device links 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. It turns out that even for actual tunneled USB3 devices it can't be assumed that the thunderbolt driver providing the tunnel is loaded before the tunneled USB3 device is created. The tunnel can be created by BIOS and remain in use by thunderbolt/USB4 host driver once it loads. Solve this by making the device link "stateless", which doesn't create a driver presence order dependency between the supplier and consumer drivers. It still guarantees correct suspend/resume and shutdown ordering. cc: Mario Limonciello Fixes: f1bfb4a6fed6 ("usb: acpi: add device link between tunneled USB3 device and USB4 Host Interface") Tested-by: Harry Wentland Signed-off-by: Mathias Nyman Reviewed-by: Mika Westerberg Tested-by: Mario Limonciello Link: https://lore.kernel.org/r/20241024131355.3836538-1-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/usb-acpi.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/usb/core/usb-acpi.c b/drivers/usb/core/usb-acpi.c index 21585ed89ef84..03c22114214b5 100644 --- a/drivers/usb/core/usb-acpi.c +++ b/drivers/usb/core/usb-acpi.c @@ -170,11 +170,11 @@ static int usb_acpi_add_usb4_devlink(struct usb_device *udev) struct fwnode_handle *nhi_fwnode __free(fwnode_handle) = fwnode_find_reference(dev_fwnode(&port_dev->dev), "usb4-host-interface", 0); - if (IS_ERR(nhi_fwnode)) + if (IS_ERR(nhi_fwnode) || !nhi_fwnode->dev) return 0; link = device_link_add(&port_dev->child->dev, nhi_fwnode->dev, - DL_FLAG_AUTOREMOVE_CONSUMER | + DL_FLAG_STATELESS | DL_FLAG_RPM_ACTIVE | DL_FLAG_PM_RUNTIME); if (!link) { -- 2.39.5