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SubjectRe: [PATCH v2] usb: dwc3: Prevent indefinite sleep in _dwc3_set_mode during suspend/resume
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Hi Felipe,

On 09/03/18 14:47, Roger Quadros 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()
>
> To fix this instead of waiting indefinitely with wait_event_lock_irq()
> we use wait_event_interruptible_lock_irq_timeout() and print
> and error message if there was a timeout.
>
> Signed-off-by: Roger Quadros <rogerq@ti.com>

Thanks for picking this for -next.
Is it better to have this in v4.16-rc fixes?
and also stable? v4.12+

> ---
>
> Changelog:
>
> v2:
> - use wait_event_interruptible_lock_irq_timeout() instead of wait_event_lock_irq()
>
> drivers/usb/dwc3/gadget.c | 23 ++++++++++++++++++++---
> 1 file changed, 20 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index 2bda4eb..7c3a6e4 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -1950,6 +1950,7 @@ static int dwc3_gadget_stop(struct usb_gadget *g)
> struct dwc3 *dwc = gadget_to_dwc(g);
> unsigned long flags;
> int epnum;
> + u32 tmo_eps = 0;
>
> spin_lock_irqsave(&dwc->lock, flags);
>
> @@ -1960,6 +1961,7 @@ static int dwc3_gadget_stop(struct usb_gadget *g)
>
> for (epnum = 2; epnum < DWC3_ENDPOINTS_NUM; epnum++) {
> struct dwc3_ep *dep = dwc->eps[epnum];
> + int ret;
>
> if (!dep)
> continue;
> @@ -1967,9 +1969,24 @@ static int dwc3_gadget_stop(struct usb_gadget *g)
> if (!(dep->flags & DWC3_EP_END_TRANSFER_PENDING))
> continue;
>
> - wait_event_lock_irq(dep->wait_end_transfer,
> - !(dep->flags & DWC3_EP_END_TRANSFER_PENDING),
> - dwc->lock);
> + ret = wait_event_interruptible_lock_irq_timeout(dep->wait_end_transfer,
> + !(dep->flags & DWC3_EP_END_TRANSFER_PENDING),
> + dwc->lock, msecs_to_jiffies(5));
> +
> + if (ret <= 0) {
> + /* Timed out or interrupted! There's nothing much
> + * we can do so we just log here and print which
> + * endpoints timed out at the end.
> + */
> + tmo_eps |= 1 << epnum;
> + dep->flags &= DWC3_EP_END_TRANSFER_PENDING;
> + }
> + }
> +
> + if (tmo_eps) {
> + dev_err(dwc->dev,
> + "end transfer timed out on endpoints 0x%x [bitmap]\n",
> + tmo_eps);
> }
>
> out:
>

--
cheers,
-roger

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

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