Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1500132

Re: [PATCH v2] usb: dwc3: gadget: Wait for end transfer complete before free irq

Show all headers | View raw

[Multipart message — attachments visible in raw view] - view raw

Hi,

Baolin Wang <baolin.wang@linaro.org> writes:
>>>> 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.

heh, 100us *is* enough. However we still get an IRQ because we requested
for it. If you want to fix this, then you need to find a way to get rid
of that 100us udelay() and add a proper wait_for_completion() to delay
execution until command complete IRQ fires up.

-- 
balbi

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH v2] usb: dwc3: gadget: Wait for end transfer complete before free irq Baolin Wang <baolin.wang@linaro.org> - 2016-10-12 13:40 +0200
  Re: [PATCH v2] usb: dwc3: gadget: Wait for end transfer complete before free irq Felipe Balbi <balbi@kernel.org> - 2016-10-13 09:30 +0200
    Re: [PATCH v2] usb: dwc3: gadget: Wait for end transfer complete  before free irq Baolin Wang <baolin.wang@linaro.org> - 2016-10-13 09:40 +0200
      Re: [PATCH v2] usb: dwc3: gadget: Wait for end transfer complete before free irq Felipe Balbi <balbi@kernel.org> - 2016-10-13 10:00 +0200
        Re: [PATCH v2] usb: dwc3: gadget: Wait for end transfer complete  before free irq Baolin Wang <baolin.wang@linaro.org> - 2016-10-13 10:10 +0200
          Re: [PATCH v2] usb: dwc3: gadget: Wait for end transfer complete before free irq Felipe Balbi <balbi@kernel.org> - 2016-10-13 12:00 +0200
            Re: [PATCH v2] usb: dwc3: gadget: Wait for end transfer complete before free irq Felipe Balbi <balbi@kernel.org> - 2016-10-13 13:00 +0200
              Re: [PATCH v2] usb: dwc3: gadget: Wait for end transfer complete  before free irq Baolin Wang <baolin.wang@linaro.org> - 2016-10-13 13:20 +0200
                Re: [PATCH v2] usb: dwc3: gadget: Wait for end transfer complete before free irq Felipe Balbi <balbi@kernel.org> - 2016-10-13 13:30 +0200
                Re: [PATCH v2] usb: dwc3: gadget: Wait for end transfer complete  before free irq Baolin Wang <baolin.wang@linaro.org> - 2016-10-13 15:10 +0200
                Re: [PATCH v2] usb: dwc3: gadget: Wait for end transfer complete before free irq Felipe Balbi <balbi@kernel.org> - 2016-10-13 15:40 +0200
                Re: [PATCH v2] usb: dwc3: gadget: Wait for end transfer complete  before free irq Baolin Wang <baolin.wang@linaro.org> - 2016-10-14 09:10 +0200
                Re: [PATCH v2] usb: dwc3: gadget: Wait for end transfer complete before free irq Felipe Balbi <balbi@kernel.org> - 2016-10-14 09:50 +0200
                Re: [PATCH v2] usb: dwc3: gadget: Wait for end transfer complete  before free irq Baolin Wang <baolin.wang@linaro.org> - 2016-10-14 11:20 +0200
                Re: [PATCH v2] usb: dwc3: gadget: Wait for end transfer complete before free irq Felipe Balbi <balbi@kernel.org> - 2016-10-14 12:00 +0200
                Re: [PATCH v2] usb: dwc3: gadget: Wait for end transfer complete  before free irq Alan Stern <stern@rowland.harvard.edu> - 2016-10-14 16:40 +0200
                Re: [PATCH v2] usb: dwc3: gadget: Wait for end transfer complete before free irq Felipe Balbi <balbi@kernel.org> - 2016-10-17 10:20 +0200

csiph-web