Re: [PATCH] usb: dwc3: gadget: Propagate core init errors to UDC during pullup

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

On Wed, Jun 14, 2023, Krishna Kurapati wrote:
> In scenarios where pullup relies on resume (get sync) to initialize
> the controller and set the run stop bit, then core_init is followed by
> gadget_resume which will eventually set run stop bit.
> 
> But in cases where the core_init fails, the return value is not sent
> back to udc appropriately. So according to UDC the controller has
> started but in reality we never set the run stop bit.
> 
> On systems like Android, there are uevents sent to HAL depending on
> whether the configfs_bind / configfs_disconnect were invoked. In the
> above mentioned scnenario, if the core init fails, the run stop won't
> be set and the cable plug-out won't result in generation of any
> disconnect event and userspace would never get any uevent regarding
> cable plug out and we never call pullup(0) again. Furthermore none of
> the next Plug-In/Plug-Out's would be known to configfs.
> 
> Return back the appropriate result to UDC to let the userspace/
> configfs know that the pullup failed so they can take appropriate
> action.
> 
> Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com>
> ---
>  drivers/usb/dwc3/gadget.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index 578804dc29ca..27cb671e18e3 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -2747,7 +2747,9 @@ static int dwc3_gadget_pullup(struct usb_gadget *g, int is_on)
>  	ret = pm_runtime_get_sync(dwc->dev);
>  	if (!ret || ret < 0) {
>  		pm_runtime_put(dwc->dev);
> -		return 0;
> +		if (ret < 0)
> +			pm_runtime_set_suspended(dwc->dev);
> +		return ret;
>  	}
>  
>  	if (dwc->pullups_connected == is_on) {
> -- 
> 2.40.0
> 

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

Thanks,
Thinh