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

[Krishna Kurapati]

On 8/28/2026 9:37 PM, Matt Eaton wrote:
> On Fri, Aug 28, 2026 at 3:53 PM Krzysztof Kozlowski <krzk@xxxxxxxxxx> wrote:
> > On 28/08/2026 15:18, Matt Eaton wrote:
> > > On Fri, Aug 28, 2026 at 2:39 PM Krzysztof Kozlowski <krzk@xxxxxxxxxx> wrote:
> > > > On 28/08/2026 14:37, Matt Eaton via B4 Relay wrote:
> > > > > From: Matt Eaton <linux@xxxxxxxxxxxxxx>
> > > > >
> > > > > 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@xxxxxxxxxxxxxx>
> > > > > ---
> > > > >   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@xxxxxxxxxxxxxxxx/

Regards,
Krishna,