Re: [RESEND PATCH v3 1/2] usb: dwc3: gadget: Add disconnect checking when changing function dynamically

From: Janusz Dziedzic
Date: Thu Oct 13 2016 - 05:23:31 EST


On 13 October 2016 at 10:21, Baolin Wang <baolin.wang@xxxxxxxxxx> wrote:
> Hi,
>
> On 13 October 2016 at 16:16, Janusz Dziedzic <janusz.dziedzic@xxxxxxxxx> wrote:
>> On 13 October 2016 at 09:37, Baolin Wang <baolin.wang@xxxxxxxxxx> wrote:
>>> Hi,
>>>
>>> On 13 October 2016 at 15:06, Felipe Balbi <balbi@xxxxxxxxxx> wrote:
>>>>
>>>> Hi,
>>>>
>>>> Baolin Wang <baolin.wang@xxxxxxxxxx> writes:
>>>>> When system has stpped the gadget, we should avoid queuing any requests
>>>>
>>>> queueing is *not* a problem. Starting is. In fact, that's what your
>>>> patch is doing.
>>>
>>> OK.
>>>
>>>>
>>>>> which will cause tranfer failed. Thus adding some disconnect checking to
>>>> ^^^^^^^
>>>> transfer
>>>
>>> Sorry for spelling mistake, will fix it.
>>>
>>>>
>>>>> avoid this situation.
>>>>>
>>>>> Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxx>
>>>>> ---
>>>>> Changes since v2:
>>>>> - Move disconnect checking into dwc3_send_gadget_ep_cmd().
>>>>> - Rename completion name and issue complete() at one place.
>>>>> - Move completion initialization into dwc3_gadget_init().
>>>>>
>>>>> Changes since v1:
>>>>> - Split into 2 separate ptaches.
>>>>> - Choose complete mechanism instead of polling.
>>>>> ---
>>>>> drivers/usb/dwc3/gadget.c | 3 +++
>>>>> 1 file changed, 3 insertions(+)
>>>>>
>>>>> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
>>>>> index 1783406..ca2ae5b 100644
>>>>> --- a/drivers/usb/dwc3/gadget.c
>>>>> +++ b/drivers/usb/dwc3/gadget.c
>>>>> @@ -241,6 +241,9 @@ int dwc3_send_gadget_ep_cmd(struct dwc3_ep *dep, unsigned cmd,
>>>>> int susphy = false;
>>>>> int ret = -EINVAL;
>>>>>
>>>>> + if (!dwc->pullups_connected)
>>>>> + return -ESHUTDOWN;
>>>>> +
>>
>> you skip trace_dwc3_gadget_ep_cmd()
>
> Yes, we did not need trace here since we did not send out the command.
>
What in such case: enumeration will not work and this will be because
this ESHUTDOWN or wrong pullups_connected usage. Without a trace you
will not know where the problem is.
In my opinion this trace could be useful.

BR
Janusz

>>
>> BR
>> Janusz
>>
>>>>> /*
>>>>> * Synopsys Databook 2.60a states, on section 6.3.2.5.[1-8], that if
>>>>> * we're issuing an endpoint command, we must check if
>>>>> --
>>>>> 1.7.9.5
>>>>>
>>>>> --
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>>>>> the body of a message to majordomo@xxxxxxxxxxxxxxx
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>>>>
>>>> --
>>>> balbi
>>>
>>>
>>>
>>> --
>>> Baolin.wang
>>> Best Regards
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe linux-usb" in
>>> the body of a message to majordomo@xxxxxxxxxxxxxxx
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>
>
>
> --
> Baolin.wang
> Best Regards