Re: [PATCH v2 1/1] usb: dwc3: Fix default mode initialization

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

On Wed, Oct 25, 2023, Alexander Stein wrote:
> The default mode, configurable by DT, shall be set before usb role switch
> driver is registered. Otherwise there is a race between default mode
> and mode set by usb role switch driver.
> 
> Fixes: 98ed256a4dbad ("usb: dwc3: Add support for role-switch-default-mode binding")
> Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
> ---
> This is a different approach to [1] to fix the race upon dwc3 role
> initialization. dwc3_set_mode() needs to be called in dwc3_setup_role_switch()
> to ensure the mode is initialized.
> The usb role switch driver probe might be delayed or defered for some unrelated
> reason, leaving the dwc3 mode unitialized if dwc3_set_mode() is not called here.
> 
> [1] https://urldefense.com/v3/__https://lore.kernel.org/linux-usb/2176034.Icojqenx9y@steina-w/T/__;!!A4F2R9G_pg!Zc8CHjnvYetlp6H8Sd2mY11RaHe8fPpI0U0qtNjnx7c3vPF7Gf82Icsdr8cZG6J6A7HbdZ95TWtLZD1Z7QIUYrWXO-POFclME57B$ 
> 
>  drivers/usb/dwc3/drd.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/dwc3/drd.c b/drivers/usb/dwc3/drd.c
> index 039bf241769af..57ddd2e43022e 100644
> --- a/drivers/usb/dwc3/drd.c
> +++ b/drivers/usb/dwc3/drd.c
> @@ -505,6 +505,7 @@ static int dwc3_setup_role_switch(struct dwc3 *dwc)
>  		dwc->role_switch_default_mode = USB_DR_MODE_PERIPHERAL;
>  		mode = DWC3_GCTL_PRTCAP_DEVICE;
>  	}
> +	dwc3_set_mode(dwc, mode);
>  
>  	dwc3_role_switch.fwnode = dev_fwnode(dwc->dev);
>  	dwc3_role_switch.set = dwc3_usb_role_switch_set;
> @@ -526,7 +527,6 @@ static int dwc3_setup_role_switch(struct dwc3 *dwc)
>  		}
>  	}
>  
> -	dwc3_set_mode(dwc, mode);
>  	return 0;
>  }
>  #else
> -- 
> 2.34.1
> 

This should Cc stable.

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

Thanks,
Thinh