Re: [PATCH v4 4/4] usb: dwc3: Notify XHCI core of tunneled status

[Konrad Dybcio]

On 10/3/26 3:23 AM, Thinh Nguyen wrote:
> On Tue, Sep 29, 2026, Konrad Dybcio wrote:
>> From: Konrad Dybcio <konrad.dybcio@xxxxxxxxxxxxxxxx>
>>
>> The Thunderbolt framework relies on the USB core to create device links
>> for tunneled ports, so that the USB3 controller is only kept
>> runtime-resumed for the duration of the tunneling. This depends on
>> first knowing whether a connection is tunneled or native.
>>
>> Add the logic to handle that for DWC3 controllers.
>>
>> Assisted-by: LLM
>> Signed-off-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxxxxxxxx>
>> ---

[...]

>> +	/* Not all DWC3 instances have CIO HW, trust the platform firmware */
>> +	if (!device_property_present(dwc->dev, "usb4-host-interface"))
> 
> Can we pass this as a dwc3 property from your glue driver instead,
> inferred from the compatible string? (ie. add dwc->has_cio)

We have both CIO and non-CIO hosts with the exact same compatible
strings on the SoCs that support it :/

Ack to other comments. If we need to wait for this dt property,
would you be open to getting patches 1-3 merged in meantime?

Or maybe we can lean on the fact that there exist dwc3+ACPI devices
that could consume this property too and sneak by ;)

Konrad