Re: [PATCH] usb: dwc2: Disable gadget descriptor DMA for Sophgo CV18XX/SG200X

[Thinh Nguyen]

On Sat, Oct 24, 2026, Chen-Yu Yeh wrote:
> dwc2_set_cv1800_params() disables gadget DMA (g_dma) but leaves
> g_dma_desc at its default, which dwc2_set_default_params() takes from
> the hardware capability. Descriptor DMA requires g_dma, so
> dwc2_check_params() rejects the combination at probe time:
> 
>   dwc2 4340000.usb: dwc2_check_params: Invalid parameter g_dma_desc=1
> 
> The check then clears g_dma_desc, so the final configuration is
> already correct and only the warning is spurious. Disable g_dma_desc
> together with g_dma in the platform parameters instead.
> 
> The gadget parameters are only set up when dr_mode is "peripheral" or
> "otg". All in-tree CV18XX/SG200X boards use "host", which is why this
> has gone unnoticed.
> 
> Tested on Milk-V Duo 256M (SG2002) with CONFIG_USB_DWC2_DUAL_ROLE=y and
> dr_mode = "peripheral": the warning is gone.
> 
> Fixes: 63aa7ab955e7 ("usb: dwc2: add support for Sophgo CV18XX/SG200X series SoC")
> Signed-off-by: Chen-Yu Yeh <chenyou910331@xxxxxxxxx>
> ---
>  drivers/usb/dwc2/params.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/usb/dwc2/params.c b/drivers/usb/dwc2/params.c
> index 091bfcfef753..6941705e426d 100644
> --- a/drivers/usb/dwc2/params.c
> +++ b/drivers/usb/dwc2/params.c
> @@ -226,6 +226,7 @@ static void dwc2_set_cv1800_params(struct dwc2_hsotg *hsotg)
>  	p->otg_caps.srp_support = false;
>  	p->host_dma = false;
>  	p->g_dma = false;
> +	p->g_dma_desc = false;
>  	p->speed = DWC2_SPEED_PARAM_HIGH;
>  	p->phy_type = DWC2_PHY_TYPE_PARAM_UTMI;
>  	p->phy_utmi_width = 16;
> -- 
> 2.43.0
> 
> 

Acked-by: Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx>

Thanks,
Thinh