linux-kernel - Re: [PATCH] usb: dwc3: Prevent indefinite sleep in _dwc3_set

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Date:   Wed, 28 Feb 2018 11:04:23 +0800
From:   Baolin Wang <baolin.wang@...aro.org>
To:     Roger Quadros <rogerq@...com>
Cc:     Felipe Balbi <balbi@...nel.org>, USB <linux-usb@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] usb: dwc3: Prevent indefinite sleep in _dwc3_set_mode
 during suspend/resume

Hi Roger,

On 27 February 2018 at 19:22, Roger Quadros <rogerq@...com> wrote:
> In the following test we get stuck by sleeping forever in _dwc3_set_mode()
> after which dual-role switching doesn't work.
>
> On dra7-evm's dual-role port,
> - Load g_zero gadget driver and enumerate to host
> - suspend to mem
> - disconnect USB cable to host and connect otg cable with Pen drive in it.
> - resume system
> - we sleep indefinitely in _dwc3_set_mode due to.
>   dwc3_gadget_exit()->usb_del_gadget_udc()->udc_stop()->
>         dwc3_gadget_stop()->wait_event_lock_irq()
>
> Let's clear the DWC3_EP_END_TRANSFER_PENDING flag on all endpoints
> so we don't wait in dwc3_gadget_stop().

I am curious why the DWC3_DEPEVT_EPCMDCMPLT event was not triggered
any more when you executed the DWC3_DEPCMD_ENDTRANSFER command?

>
> Signed-off-by: Roger Quadros <rogerq@...com>
> ---
>  drivers/usb/dwc3/gadget.c | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
>
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index 2bda4eb..0a360da 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -3273,6 +3273,20 @@ int dwc3_gadget_init(struct dwc3 *dwc)
>
>  void dwc3_gadget_exit(struct dwc3 *dwc)
>  {
> +       int epnum;
> +       unsigned long flags;
> +
> +       spin_lock_irqsave(&dwc->lock, flags);
> +       for (epnum = 2; epnum < DWC3_ENDPOINTS_NUM; epnum++) {
> +               struct dwc3_ep  *dep = dwc->eps[epnum];
> +
> +               if (!dep)
> +                       continue;
> +
> +               dep->flags &= ~DWC3_EP_END_TRANSFER_PENDING;
> +       }
> +       spin_unlock_irqrestore(&dwc->lock, flags);
> +
>         usb_del_gadget_udc(&dwc->gadget);
>         dwc3_gadget_free_endpoints(dwc);
>         dma_free_coherent(dwc->sysdev, DWC3_BOUNCE_SIZE, dwc->bounce,
> --

-- 
Baolin.wang
Best Regards