Hi, Baolin Wang <baolin.wang@xxxxxxxxxx> writes: > Hi, > > On 13 October 2016 at 15:02, Felipe Balbi <balbi@xxxxxxxxxx> wrote: >> >> Hi, >> >> Baolin Wang <baolin.wang@xxxxxxxxxx> 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. It seems as if *that* should be fixed. We should start actually waiting for Command Complete IRQ. -- balbi
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