Re: [PATCH 1/2] dt-bindings: usb: xhci: add xhci-no-soft-retry-quirk

[Krishna Kurapati <krishna.kurapati@oss.qualcomm.com>]

On 8/28/2026 9:37 PM, Matt Eaton wrote:
> On Fri, Aug 28, 2026 at 3:53 PM Krzysztof Kozlowski <krzk@kernel.org> wrote:
>>
>> On 28/08/2026 15:18, Matt Eaton wrote:
>>> On Fri, Aug 28, 2026 at 2:39 PM Krzysztof Kozlowski <krzk@kernel.org> wrote:
>>>>
>>>> On 28/08/2026 14:37, Matt Eaton via B4 Relay wrote:
>>>>> From: Matt Eaton <linux@divinehawk.com>
>>>>>
>>>>> Document the xhci-no-soft-retry-quirk property, added in the
>>>>> following patch.
>>>>>
>>>>> snps,dwc3-common.yaml refs usb-xhci.yaml for every dr_mode other than
>>>>> peripheral, so a host-mode dwc3 node inherits it and dt_binding_check
>>>>> accepts it there.
>>>>
>>>> I do not understand how this sentence is relevant. Please describe the
>>>> hardware needing this.
>>>
>>> I came across this while porting the UniFi Travel Router (IPQ4018),
>>> the stock Qualcomm kernel is 4.4.60 which predates the soft retry
>>> code. The command ring hangs if you disconnect the device while it's
>>> transmitting. Reproducible consistently when using USB to tether to a
>>> phone.
>>>
>>>>>
>>>>> Signed-off-by: Matt Eaton <linux@divinehawk.com>
>>>>> ---
>>>>>   Documentation/devicetree/bindings/usb/usb-xhci.yaml | 4 ++++
>>>>>   1 file changed, 4 insertions(+)
>>>>>
>>>>> diff --git a/Documentation/devicetree/bindings/usb/usb-xhci.yaml b/Documentation/devicetree/bindings/usb/usb-xhci.yaml
>>>>> index 4238ae896ef6..5d67a41658f7 100644
>>>>> --- a/Documentation/devicetree/bindings/usb/usb-xhci.yaml
>>>>> +++ b/Documentation/devicetree/bindings/usb/usb-xhci.yaml
>>>>> @@ -25,6 +25,10 @@ properties:
>>>>>       description: Set if the controller has broken port disable mechanism
>>>>>       type: boolean
>>>>>
>>>>> +  xhci-no-soft-retry-quirk:
>>>>> +    description: Set if the controller cannot perform xHCI Soft Retry correctly
>>>>
>>>> Why isn't this implied by compatible? Looks like controller's property.
>>>
>>> The xhci device is created by dwc3 core as a child device, and so
>>> xhci_plat_probe() is used. I think a DT property is the right
>>> approach, similar to quirk-broken-port-ped, but to set
>>> XHCI_NO_SOFT_RETRY.
>>
>> Linux driver behavior should not matter here. DT property for telling
>> Linux what to do is not the right approach. As I said, it's implied by
>> compatible unless you bring hardware reasons why it is not. Driver
>> reasons don't matter.
> 
> Will rework without DT property. Appreciate the feedback!
> 
If you have any upstream QC target that needs this, you can use the 
following patch as reference:

https://lore.kernel.org/all/20260723-dwc3-skip-init-quirk-v1-1-97682bb44ebd@oss.qualcomm.com/

Regards,
Krishna,