On Wed, Oct 28, 2020 at 04:43:10PM -0700, Wesley Cheng wrote:
> The DWC3 runtime suspend routine checks for the USB connected parameter to
> determine if the controller can enter into a low power state. The
> connected state is only set to false after receiving a disconnect event.
> However, in the case of a device initiated disconnect (i.e. UDC unbind),
> the controller is halted and a disconnect event is never generated. Set
> the connected flag to false if issuing a device initiated disconnect to
> allow the controller to be suspended.
>
> Signed-off-by: Wesley Cheng <wcheng@xxxxxxxxxxxxxx>
> ---
> drivers/usb/dwc3/gadget.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index 5d879b7606d5..6364429b2122 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -1995,6 +1995,11 @@ static int dwc3_gadget_pullup(struct usb_gadget *g, int is_on)
> unsigned long flags;
> int ret;
>
> + if (pm_runtime_suspended(dwc->dev)) {
> + pm_request_resume(dwc->dev);
> + return 0;
> + }
Isn't this racy? What happens if the controller was active but a
runtime suspend occurs right here?
Alan Stern
> +
> is_on = !!is_on;
>
> /*
> @@ -2050,6 +2055,7 @@ static int dwc3_gadget_pullup(struct usb_gadget *g, int is_on)
> dwc->ev_buf->lpos = (dwc->ev_buf->lpos + count) %
> dwc->ev_buf->length;
> }
> + dwc->connected = false;
> }
>
> ret = dwc3_gadget_run_stop(dwc, is_on, false);
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
