Re: [PATCH] usb: typec: port-mapper: Only match USB4 port if host interface is available

[Heikki Krogerus]

On Fri, Sep 25, 2026 at 03:16:50PM +0200, Marek Maslanka wrote:
> typec_port_match() adds a component match for the USB4 port whenever a
> USB 3.x port that shares the _PLD with the Type-C connector has the
> "usb4-host-interface" property, regardless of whether a USB4 port can
> ever be registered for it. The component framework binds the aggregate
> device only once every match has found its component, so if the USB4
> port never shows up, the USB 2.0 and USB 3.x ports are not linked to the
> connector either: the "connector" symlinks are never created and USB
> devices enumerated on those ports are never linked with the Type-C
> partner.
> 
> This happens in at least two cases:
> 
> 1. CONFIG_USB4 is not reachable from the Type-C core, i.e. CONFIG_USB4=n,
>    or CONFIG_USB4=m with CONFIG_TYPEC=y as in the x86_64 gki_defconfig.
>    usb4_usb3_port_match() is then a stub that always returns false.
> 
> 2. The firmware references a USB4 host interface that is disabled. For
>    example, on Intel Alder Lake-N (ChromeOS Nissa) the TCSS xHCI USB3
>    ports (SS01-SS04) reference TDM0/TDM1, whose _STA returns 0 because
>    the SoC has no integrated Thunderbolt/USB4 and the DMA controllers
>    are disabled in TCSS DEVEN. No PCI device is enumerated for them.
> 
> Only add the USB4 component match if CONFIG_USB4 is reachable and the
> referenced host interface is available and has been enumerated as a
> device. The latter mirrors the check in usb_acpi_add_usb4_devlink(), see
> commit 623dae3e7084 ("usb: acpi: fix boot hang due to early incorrect
> 'tunneled' USB3 device links").
> 
> Fixes: 4fd7a1f0f7f2 ("usb: typec: Connect Type-C port with associated USB4 port")

+Alan

> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Marek Maslanka <mmaslanka@xxxxxxxxxx>

Acked-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>

> ---
>  drivers/usb/typec/port-mapper.c | 21 +++++++++++++++++++--
>  1 file changed, 19 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/typec/port-mapper.c b/drivers/usb/typec/port-mapper.c
> index cdbb7c11d714..3a97b084c3bd 100644
> --- a/drivers/usb/typec/port-mapper.c
> +++ b/drivers/usb/typec/port-mapper.c
> @@ -42,6 +42,23 @@ static int usb4_port_compare(struct device *dev, void *fwnode)
>  	return usb4_usb3_port_match(dev, fwnode);
>  }
>  
> +static bool typec_has_usb4_host_interface(const struct fwnode_handle *fwnode)
> +{
> +	if (!IS_REACHABLE(CONFIG_USB4))
> +		return false;
> +
> +	struct fwnode_handle *nhi_fwnode __free(fwnode_handle) =
> +		fwnode_find_reference(fwnode, "usb4-host-interface", 0);
> +
> +	/*
> +	 * The USB4 port can only appear if the host interface is enabled in
> +	 * the firmware and has been enumerated as a device. The latter is
> +	 * the same check as in usb_acpi_add_usb4_devlink().
> +	 */
> +	return !IS_ERR(nhi_fwnode) && fwnode_device_is_available(nhi_fwnode) &&
> +	       nhi_fwnode->dev;
> +}
> +
>  static int typec_port_compare(struct device *dev, void *fwnode)
>  {
>  	return device_match_fwnode(dev, fwnode);
> @@ -64,11 +81,11 @@ static int typec_port_match(struct device *dev, void *data)
>  				    adev_fwnode);
>  
>  		/*
> -		 * If dev is USB 3.x port, it may have reference to the
> +		 * If dev is USB 3.x port, it may have reference to an available
>  		 * USB4 host interface in which case we can also link the
>  		 * Type-C port with the USB4 port.
>  		 */
> -		if (fwnode_property_present(adev_fwnode, "usb4-host-interface"))
> +		if (typec_has_usb4_host_interface(adev_fwnode))
>  			component_match_add(&arg->port->dev, &arg->match,
>  					    usb4_port_compare, adev_fwnode);
>  	}
> -- 
> 2.56.0.rc1.315.gc6ed9934b7-goog

-- 
heikki