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Message-ID: <0cd4f5f9-f729-f638-098a-285bbd5f8542@synopsys.com>
Date: Thu, 23 Apr 2020 10:35:42 +0000
From: Minas Harutyunyan <Minas.Harutyunyan@...opsys.com>
To: Fabrice Gasnier <fabrice.gasnier@...com>,
Minas Harutyunyan <Minas.Harutyunyan@...opsys.com>,
"balbi@...nel.org" <balbi@...nel.org>
CC: "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-stm32@...md-mailman.stormreply.com"
<linux-stm32@...md-mailman.stormreply.com>,
"amelie.delaunay@...com" <amelie.delaunay@...com>
Subject: Re: [PATCH 1/4] usb: dwc2: gadget: move gadget resume after the core
is in L0 state
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@...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
>>
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