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Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Subject: Re: [PATCH v2 4/5] usb: dwc3: Allow end transfer commands to be sent during soft disconnect Content-Language: en-US From: Wesley Cheng To: Thinh Nguyen , "balbi@kernel.org" , "gregkh@linuxfoundation.org" CC: "linux-kernel@vger.kernel.org" , "linux-usb@vger.kernel.org" , "quic_jackp@quicinc.com" References: <20220713003523.29309-1-quic_wcheng@quicinc.com> <20220713003523.29309-5-quic_wcheng@quicinc.com> <98623d02-cde4-b036-a85c-9325b58c7eab@quicinc.com> <5d0cf380-e045-fcec-639f-ac2f6a187ca8@synopsys.com> <5a57d5b9-b81e-bb09-998b-2915d9ab6b2f@quicinc.com> In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.80.80.8] X-ClientProxiedBy: nasanex01a.na.qualcomm.com (10.52.223.231) To nalasex01b.na.qualcomm.com (10.47.209.197) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Thinh, On 7/21/2022 5:04 PM, Wesley Cheng wrote: > Hi Thinh, > > On 7/21/2022 5:00 PM, Thinh Nguyen wrote: >> On 7/21/2022, Wesley Cheng wrote: >>> Hi Thinh, >>> >>> On 7/21/2022 3:20 PM, Thinh Nguyen wrote: >>>> On 7/21/2022, Wesley Cheng wrote: >>>>> Hi Thinh, >>>>> >>>>> On 7/21/2022 3:08 PM, Thinh Nguyen wrote: >>>>>> Hi Wesley, >>>>>> >>>>>> On 7/12/2022, Wesley Cheng wrote: >>>>>>> If soft disconnect is in progress, allow the endxfer command to be >>>>>>> sent, >>>>>>> without this, there is an issue where the stop active transfer call >>>>>>> (during pullup disable) wouldn't actually issue the endxfer command, >>>>>>> while clearing the DEP flag. >>>>>>> >>>>>>> In addition, if the DWC3_EP_DELAY_STOP flag was set before soft >>>>>>> disconnect >>>>>>> started (i.e. from the dequeue path), ensure that when the EP0 >>>>>>> transaction >>>>>>> completes during soft disconnect, to issue the endxfer with the >>>>>>> force >>>>>>> parameter set, as it does not expect a command complete event. >>>>>>> >>>>>>> Fixes: e4cf6580ac740 ("usb: dwc3: gadget: Wait for ep0 xfers to >>>>>>> complete during dequeue") >>>>>>> Suggested-by: Thinh Nguyen >>>>>>> Signed-off-by: Wesley Cheng >>>>>>> --- >>>>>>> Link: >>>>>>> https://urldefense.com/v3/__https://lore.kernel.org/linux-usb/1a1a5485-790e-79ce-f5a6-1e96d9b49a47@synopsys.com/__;!!A4F2R9G_pg!cXW2TlALYWnXNPg-NoMFUrQ8K1egEZiQizZ5CA1DOM1Gcw4tfOULy-_2eMGvL8pQPte5dScFON-0wxH2eXu8ijEQUbs$ >>>>>>> >>>>>>> >>>>>>> >>>>>>>      drivers/usb/dwc3/ep0.c    | 3 +-- >>>>>>>      drivers/usb/dwc3/gadget.c | 5 ++++- >>>>>>>      2 files changed, 5 insertions(+), 3 deletions(-) >>>>>>> >>>>>>> diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c >>>>>>> index 506ef717fdc0..5851b0e9db0a 100644 >>>>>>> --- a/drivers/usb/dwc3/ep0.c >>>>>>> +++ b/drivers/usb/dwc3/ep0.c >>>>>>> @@ -290,8 +290,7 @@ void dwc3_ep0_out_start(struct dwc3 *dwc) >>>>>>>              if (!(dwc3_ep->flags & DWC3_EP_DELAY_STOP)) >>>>>>>                  continue; >>>>>>>      -        dwc3_ep->flags &= ~DWC3_EP_DELAY_STOP; >>>>>> >>>>>> If we don't clear this flag here, >>>>>> >>>>> >>>>> This is why I added the dwc->connected argument to control the >>>>> "interrupt" argument. >>>>> >>>>>>> - dwc3_stop_active_transfer(dwc3_ep, true, true); >>>>>>> +        dwc3_stop_active_transfer(dwc3_ep, true, dwc->connected); >>>>>>>          } >>>>>>>      } >>>>>>>      diff --git a/drivers/usb/dwc3/gadget.c >>>>>>> b/drivers/usb/dwc3/gadget.c >>>>>>> index ee85b773e3fe..41b7007358de 100644 >>>>>>> --- a/drivers/usb/dwc3/gadget.c >>>>>>> +++ b/drivers/usb/dwc3/gadget.c >>>>>>> @@ -1693,6 +1693,7 @@ static int __dwc3_stop_active_transfer(struct >>>>>>> dwc3_ep *dep, bool force, bool int >>>>>>>              dep->flags &= ~DWC3_EP_TRANSFER_STARTED; >>>>>>>          else if (!ret) >>>>>>>              dep->flags |= DWC3_EP_END_TRANSFER_PENDING; >>>>>>> +    dep->flags &= ~DWC3_EP_DELAY_STOP; >>>>>>>             return ret; >>>>>>>      } >>>>>>> @@ -3686,8 +3687,10 @@ void dwc3_stop_active_transfer(struct dwc3_ep >>>>>>> *dep, bool force, >>>>>>>          if (dep->number <= 1 && dwc->ep0state != EP0_DATA_PHASE) >>>>>>>              return; >>>>>>>      +    if (interrupt && (dep->flags & DWC3_EP_DELAY_STOP)) >>>>>>> +        return; >>>>>>> + >>>>>> >>>>>> then it may not go through here. I think I made this same mistake >>>>>> in my >>>>>> previous suggestion. >>>>>> >>>>> >>>>> Since dwc->connected is set to FALSE before we call stop active >>>>> transfers, if we ever run into a situation where delayed stop is set >>>>> already, then it should go through. >>>>> >>>> >>>> Then the check for request dequeue that we did previously will not work >>>> anymore. >>>> >>> >>> Could you help clarify?  The pullup refactor kind of shifted some of >>> the previous checks we had in the dequeue path, and combined with with >>> the stop active transfer checks. >>> >>> I think there was an issue w/ the patch I submitted though.  the above >>> snippet should be replacing what is there: >>> >>> void dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force, >>>      bool interrupt) >>> { >>> ... >>>      if (!(dep->flags & DWC3_EP_TRANSFER_STARTED) || >>>          /* Following should be removed --- (dep->flags & >>> DWC3_EP_DELAY_STOP) || */ >>>          (dep->flags & DWC3_EP_END_TRANSFER_PENDING)) >>>          return; >>> >> >> Request dequeue can occur while the device is connected. The >> DWC3_EP_DELAY_STOP intention is to delay sending the End Transfer >> command until the SETUP stage is prepared. If we don't clear the flag >> before the flag check, then the End Transfer command will not go through. >> > > Thanks, got it.  Understand what you mean now.  Let me think about how > to go about it.  I probably don't see any issues as of now, because my > test does the soft disconnect, which will do the stop active transfers > forcefully. > What do you think about just removing the (dep->flags & DWC3_EP_DELAY_STOP) check? In the end, as long as the conditions are satisfied (ie we aren't in the middle of a SETUP transaction) then we don't care too much about who called dwc3_stop_active_transfer(). We would still be able to avoid issuing the endxfer here: if (dwc->ep0state != EP0_SETUP_PHASE && !dwc->delayed_status) { dep->flags |= DWC3_EP_DELAY_STOP; return 0; } Thanks Wesley Cheng