Re: [PATCH 1/4] usb: dwc2: gadget: move gadget resume after the core is in L0 state

[Minas Harutyunyan <Minas.Harutyunyan@synopsys.com>]

Hi Fabrice,

On 4/23/2020 1:27 PM, Fabrice Gasnier wrote:
> On 4/22/20 6:16 PM, Minas Harutyunyan wrote:
>> Hi Fabrice,
>>
>> On 4/22/2020 7:57 PM, Fabrice Gasnier wrote:
>>> On 4/22/20 4:48 PM, Minas Harutyunyan wrote:
>>>> Hi Fabrice,
>>>>
>>>> On 4/21/2020 4:32 PM, Fabrice Gasnier wrote:
>>>>> When the remote wakeup interrupt is triggered, lx_state is resumed from L2
>>>>> to L0 state. But when the gadget resume is called, lx_state is still L2.
>>>>> This prevents the resume callback to queue any request. Any attempt
>>>>> to queue a request from resume callback will result in:
>>>>> - "submit request only in active state" debug message to be issued
>>>>> - dwc2_hsotg_ep_queue() returns -EAGAIN
>>>>>
>>>>> Move the call to resume gadget after the core is put in DWC2_L0 state.
>>>>>
>>>>> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
>>>>> ---
>>>>>     drivers/usb/dwc2/core_intr.c | 10 +++++++---
>>>>>     1 file changed, 7 insertions(+), 3 deletions(-)
>>>>>
>>>>> diff --git a/drivers/usb/dwc2/core_intr.c b/drivers/usb/dwc2/core_intr.c
>>>>> index 876ff31..b8ebda5 100644
>>>>> --- a/drivers/usb/dwc2/core_intr.c
>>>>> +++ b/drivers/usb/dwc2/core_intr.c
>>>>> @@ -404,9 +404,11 @@ static void dwc2_handle_wakeup_detected_intr(struct dwc2_hsotg *hsotg)
>>>>>     	}
>>>>>     
>>>>>     	if (dwc2_is_device_mode(hsotg)) {
>>>>> +		enum dwc2_lx_state lx_state = hsotg->lx_state;
>>>>> +
>>>>>     		dev_dbg(hsotg->dev, "DSTS=0x%0x\n",
>>>>>     			dwc2_readl(hsotg, DSTS));
>>>>> -		if (hsotg->lx_state == DWC2_L2) {
>>>>> +		if (lx_state == DWC2_L2) {
>>>>>     			u32 dctl = dwc2_readl(hsotg, DCTL);
>>>>>     
>>>>>     			/* Clear Remote Wakeup Signaling */
>>>>> @@ -415,11 +417,13 @@ static void dwc2_handle_wakeup_detected_intr(struct dwc2_hsotg *hsotg)
>>>>>     			ret = dwc2_exit_partial_power_down(hsotg, true);
>>>>>     			if (ret && (ret != -ENOTSUPP))
>>>>>     				dev_err(hsotg->dev, "exit power_down failed\n");
>>>>> -
>>>>> -			call_gadget(hsotg, resume);
>>>>>     		}
>>>>>     		/* Change to L0 state */
>>>>>     		hsotg->lx_state = DWC2_L0;
>>>>> +
>>>>> +		/* Gadget may queue new requests upon resume to L0 state */
>>>>> +		if (lx_state == DWC2_L2)
>>>>> +			call_gadget(hsotg, resume);
>>>>>     	} else {
>>>>>     		if (hsotg->params.power_down)
>>>>>     			return;
>>>>>
>>>>
>>>> What about below patch without introducing additional variable.
>>>>
>>>> diff --git a/drivers/usb/dwc2/core_intr.c b/drivers/usb/dwc2/core_intr.c
>>>> index 876ff31261d5..543865e31c72 100644
>>>> --- a/drivers/usb/dwc2/core_intr.c
>>>> +++ b/drivers/usb/dwc2/core_intr.c
>>>> @@ -416,6 +416,8 @@ static void dwc2_handle_wakeup_detected_intr(struct
>>>> dwc2_hsotg *hsotg)
>>>>                            if (ret && (ret != -ENOTSUPP))
>>>>                                    dev_err(hsotg->dev, "exit power_down
>>>> failed\n");
>>>>
>>>> +                       /* Change to L0 state */
>>>> +                       hsotg->lx_state = DWC2_L0;
>>>
>>> Hi Minas,
>>>
>>> That was my first approach locally, but I added a variable to avoid do
>>> it twice... few lines after.
>>>
>>> But if you prefer, I can change in V2 ?
>>>
>>> Please let me know.
>>>
>>> Thanks,
>>> Fabrice
>>>
>>>>                            call_gadget(hsotg, resume);
>>>>                    }
>>>>                    /* Change to L0 state */
>>>>
>>>>
>>>> Thanks,
>>>> Minas
>>>>
>> To avoid twice setting lx_state you can add 'else' before second setting.
> 
> Hi Minas,
> 
> Thanks for your quick answer. Sure, I'll update it in v2.
> 
> Also, do you think this can/should be marked as a fix ?
> - e.g. add a Fixes tag?
> 
> Fixes: f81f46e1f530 ("usb: dwc2: implement hibernation during bus
> suspend/resume")
> 

Yes, go ahead to submit V2 with mentioned "Fixes:" tag.

Thanks,
Minas


> Please advise,
> Best Regards,
> Fabrice
> 
>>
>> diff --git a/drivers/usb/dwc2/core_intr.c b/drivers/usb/dwc2/core_intr.c
>> index 876ff31261d5..f59dabd46e60 100644
>> --- a/drivers/usb/dwc2/core_intr.c
>> +++ b/drivers/usb/dwc2/core_intr.c
>> @@ -416,10 +416,14 @@ static void
>> dwc2_handle_wakeup_detected_intr(struct dwc2_hsotg *hsotg)
>>                           if (ret && (ret != -ENOTSUPP))
>>                                   dev_err(hsotg->dev, "exit power_down
>> failed\n");
>>
>> +                       /* Change to L0 state */
>> +                       hsotg->lx_state = DWC2_L0;
>>                           call_gadget(hsotg, resume);
>>                   }
>> -               /* Change to L0 state */
>> -               hsotg->lx_state = DWC2_L0;
>> +               else {
>> +                       /* Change to L0 state */
>> +                       hsotg->lx_state = DWC2_L0;
>> +               }
>>           } else {
>>                   if (hsotg->params.power_down)
>>                           return;
>>
>>
>>
>> Am I missed something?
>>
>> Thanks,
>> Minas
>>