Re: [PATCH] usb: dwc3: Resend full Data Packet for non-compliant USB3.1 devices

[Thinh Nguyen <Thinh.Nguyen@synopsys.com>]

On Tue, Sep 15, 2026, Konrad Dybcio wrote:
> From: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
> 
> Some non-compliant devices require that a full Data Packet (and not
> only the header) is resent upon LBAD. One such device is the USB3
> protocol adapter within the Qualcomm USB4 router.
> 
> DWC3 has a toggle to enable that behavior within LLINKDBGCTRL, use it.
> 
> Signed-off-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
> ---
>  drivers/usb/dwc3/core.c | 8 ++++++++
>  drivers/usb/dwc3/core.h | 2 ++
>  2 files changed, 10 insertions(+)
> 
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index fd5c2cd36c59..d375ebee297b 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -1514,6 +1514,14 @@ int dwc3_core_init(struct dwc3 *dwc)
>  		}
>  	}
>  
> +	if (DWC3_IP_IS(DWC31) || DWC3_IP_IS(DWC32)) {
> +		for (int i = 0; i < dwc->num_usb3_ports; i++) {
> +			reg = dwc3_readl(dwc, DWC3_LLINKDBGCTRL(i));
> +			reg |= DWC3_LLINKDBGCTRL_RETRY_DP;
> +			dwc3_writel(dwc, DWC3_LLINKDBGCTRL(i), reg);
> +		}
> +	}
> +
>  	/*
>  	 * STAR 9001346572: This issue affects DWC_usb31 versions 1.80a and
>  	 * prior. When an active endpoint not currently cached in the host
> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> index 608daeb7ef10..6af644a9672d 100644
> --- a/drivers/usb/dwc3/core.h
> +++ b/drivers/usb/dwc3/core.h
> @@ -180,6 +180,8 @@
>  #define DWC3_OSTS		0xcc10
>  
>  #define DWC3_LLUCTL(n)		(0xd024 + ((n) * 0x80))
> +#define DWC3_LLINKDBGCTRL(n)	(0xd058 + ((n) * 0x80))
> +#define DWC3_LLINKDBGCTRL_RETRY_DP	BIT(31)
>  
>  /* Bit fields */
>  
> 
> ---
> base-commit: 1a1de54f7369cd2b5bac0f265910e60ad3a6b4c3
> change-id: 20260915-topic-usb3_tunneling_fixup-8c0fb73edec8
> 
> Best regards,
> --  
> Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
> 

Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>

Thanks,
Thinh