Hi, On 13 October 2016 at 15:51, Felipe Balbi <ba...@kernel.org> wrote: > > Hi, > > Baolin Wang <baolin.w...@linaro.org> writes: >> Hi, >> >> On 13 October 2016 at 15:02, Felipe Balbi <ba...@kernel.org> wrote: >>> >>> Hi, >>> >>> Baolin Wang <baolin.w...@linaro.org> writes: >>>> @@ -1742,6 +1791,17 @@ static int dwc3_gadget_stop(struct usb_gadget *g) >>>> dwc->gadget_driver = NULL; >>>> spin_unlock_irqrestore(&dwc->lock, flags); >>>> >>>> + /* >>>> + * Since the xHCI will share the same interrupt with gadget, thus >>>> when >>>> + * free the gadget irq, it will not shutdown this gadget irq line. >>>> Then >>>> + * the gadget driver can not handle the end transfer command complete >>>> + * event after free the gadget irq, which will hang the system to >>>> crash. >>>> + * >>>> + * So we should wait for the end transfer command complete event >>>> before >>>> + * free it to avoid this situation. >>>> + */ >>>> + dwc3_wait_command_complete(dwc); >>> >>> this doesn't make sense. We have already masked all interrupts before >>> getting here. We have also, already, disabled all endpoints. >> >> No, you just mask the interrupts described in DEVTEN register, and you >> did not disable the endpoint command complete event. > > True that > >>> I'm thinking this is a bug in configfs interface of Gadget API, not >>> dwc3. The only reason for this to happen would be if we get to >>> ->udc_stop() with endpoints still enabled. >>> >>> Can you check if that's the case? i.e. can you check if any endpoints >>> are still enabled when we get here? >> >> No, it is not any endpoints are still enabled. Like I said in commit >> message, we will start end transfer command when disable the endpoint, >> if the end transfer command complete event comes after we have freed >> the gadget irq, it will trigger the interrupt line all the time to >> crash the system. > > I see what the problem is. Databook tells us we *must* set CMDIOC when > issuing EndTransfer command and we should always wait for Command > Complete IRQ. However, we took a shortcut and just delayed for 100us > after issuing End Transfer.
Yes, but 100us delay is not enough in some scenarios, like changing function with configfs frequently, we will met problems. > > It seems as if *that* should be fixed. We should start actually waiting > for Command Complete IRQ. > > -- > balbi -- Baolin.wang Best Regards -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
