2023-08-01 20:13:58

by Elson Serrao

Subject: [PATCH] usb: dwc3: Properly handle processing of pending events

If dwc3 is runtime suspended we defer processing the event buffer
until resume, by setting the pending_events flag. Set this flag before
triggering resume to avoid race with the runtime resume callback.

While handling the pending events, in addition to checking the event
buffer we also need to process it. Handle this by explicitly calling
dwc3_thread_interrupt(). Also balance the runtime pm get() operation
that triggered this processing.

Cc: [email protected]
Fixes: fc8bb91bc83e ("usb: dwc3: implement runtime PM")
Signed-off-by: Elson Roy Serrao <[email protected]>
---
Change separated from below series as an independent fix based on the
earlier discussion
https://lore.kernel.org/all/[email protected]/

drivers/usb/dwc3/gadget.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 5fd067151fbf..858fe4c299b7 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -4455,9 +4455,14 @@ static irqreturn_t dwc3_check_event_buf(struct dwc3_event_buffer *evt)
u32 count;

if (pm_runtime_suspended(dwc->dev)) {
+ dwc->pending_events = true;
+ /*
+ * Trigger runtime resume. The get() function will be balanced
+ * after processing the pending events in dwc3_process_pending
+ * events().
+ */
pm_runtime_get(dwc->dev);
disable_irq_nosync(dwc->irq_gadget);
- dwc->pending_events = true;
return IRQ_HANDLED;
}

@@ -4718,6 +4723,8 @@ void dwc3_gadget_process_pending_events(struct dwc3 *dwc)
{
if (dwc->pending_events) {
dwc3_interrupt(dwc->irq_gadget, dwc->ev_buf);
+ dwc3_thread_interrupt(dwc->irq_gadget, dwc->ev_buf);
+ pm_runtime_put(dwc->dev);
dwc->pending_events = false;
enable_irq(dwc->irq_gadget);
}
--
2.17.1

2023-08-02 01:17:58

by Thinh Nguyen

Subject: Re: [PATCH] usb: dwc3: Properly handle processing of pending events

On Tue, Aug 01, 2023, Elson Roy Serrao wrote:
> If dwc3 is runtime suspended we defer processing the event buffer
> until resume, by setting the pending_events flag. Set this flag before
> triggering resume to avoid race with the runtime resume callback.
>
> While handling the pending events, in addition to checking the event
> buffer we also need to process it. Handle this by explicitly calling
> dwc3_thread_interrupt(). Also balance the runtime pm get() operation
> that triggered this processing.
>
> Cc: [email protected]
> Fixes: fc8bb91bc83e ("usb: dwc3: implement runtime PM")
> Signed-off-by: Elson Roy Serrao <[email protected]>
> ---
> Change separated from below series as an independent fix based on the
> earlier discussion
> https://urldefense.com/v3/__https://lore.kernel.org/all/[email protected]/__;!!A4F2R9G_pg!YtZ93ALEpDNTCEhf0WEyB5S090pPlKIKVtjqTOAEJdxdWbl8QG6eiRmlvfivUtD5qjKWWLX2C4fb4W8VAg5w9qasLuKB$
>
> drivers/usb/dwc3/gadget.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index 5fd067151fbf..858fe4c299b7 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -4455,9 +4455,14 @@ static irqreturn_t dwc3_check_event_buf(struct dwc3_event_buffer *evt)
> u32 count;
>
> if (pm_runtime_suspended(dwc->dev)) {
> + dwc->pending_events = true;
> + /*
> + * Trigger runtime resume. The get() function will be balanced
> + * after processing the pending events in dwc3_process_pending
> + * events().
> + */
> pm_runtime_get(dwc->dev);
> disable_irq_nosync(dwc->irq_gadget);
> - dwc->pending_events = true;
> return IRQ_HANDLED;
> }
>
> @@ -4718,6 +4723,8 @@ void dwc3_gadget_process_pending_events(struct dwc3 *dwc)
> {
> if (dwc->pending_events) {
> dwc3_interrupt(dwc->irq_gadget, dwc->ev_buf);
> + dwc3_thread_interrupt(dwc->irq_gadget, dwc->ev_buf);
> + pm_runtime_put(dwc->dev);
> dwc->pending_events = false;
> enable_irq(dwc->irq_gadget);
> }
> --
> 2.17.1
>

This fix is more complete.

Acked-by: Thinh Nguyen <[email protected]>

Thanks,
Thinh

2023-08-02 03:00:13

by 庞苏荣 (Surong Pang)

Subject: Re: [PATCH] usb: dwc3: Properly handle processing of pending events

Dears，
If there is/are event(s) in evt->buf, in dwc3_check_event_buf, dwc3_thread_interrupt will be woke up.

> > @@ -4718,6 +4723,8 @@ void dwc3_gadget_process_pending_events(struct
> > dwc3 *dwc) {
> > if (dwc->pending_events) {
> > dwc3_interrupt(dwc->irq_gadget, dwc->ev_buf);
> > + dwc3_thread_interrupt(dwc->irq_gadget, dwc->ev_buf);
> > + pm_runtime_put(dwc->dev);
> > dwc->pending_events = false;
> > enable_irq(dwc->irq_gadget);
> > }

I just want to know dwc3_thread_interrupt here is necessary or not?


> On Tue, Aug 02, 2023 8:12 Thinh Nguyen wrote:
>> On Tue, Aug 01, 2023, Elson Roy Serrao wrote:
> > If dwc3 is runtime suspended we defer processing the event buffer
> > until resume, by setting the pending_events flag. Set this flag before
> > triggering resume to avoid race with the runtime resume callback.
> >
> > While handling the pending events, in addition to checking the event
> > buffer we also need to process it. Handle this by explicitly calling
> > dwc3_thread_interrupt(). Also balance the runtime pm get() operation
> > that triggered this processing.
> >
> > Cc: [email protected]
> > Fixes: fc8bb91bc83e ("usb: dwc3: implement runtime PM")
> > Signed-off-by: Elson Roy Serrao <[email protected]>
> > ---
> > Change separated from below series as an independent fix based on the
> > earlier discussion
> > https://urldefense.com/v3/__https://lore.kernel.org/all/be57511d-2005-
> > [email protected]/__;!!A4F2R9G_pg!YtZ93ALEpDNTCEhf0WE
> > yB5S090pPlKIKVtjqTOAEJdxdWbl8QG6eiRmlvfivUtD5qjKWWLX2C4fb4W8VAg5w9qasL
> > uKB$
> >
> > drivers/usb/dwc3/gadget.c | 9 ++++++++-
> > 1 file changed, 8 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> > index 5fd067151fbf..858fe4c299b7 100644
> > --- a/drivers/usb/dwc3/gadget.c
> > +++ b/drivers/usb/dwc3/gadget.c
> > @@ -4455,9 +4455,14 @@ static irqreturn_t dwc3_check_event_buf(struct dwc3_event_buffer *evt)
> > u32 count;
> >
> > if (pm_runtime_suspended(dwc->dev)) {
> > + dwc->pending_events = true;
> > + /*
> > + * Trigger runtime resume. The get() function will be balanced
> > + * after processing the pending events in dwc3_process_pending
> > + * events().
> > + */
> > pm_runtime_get(dwc->dev);
> > disable_irq_nosync(dwc->irq_gadget);
> > - dwc->pending_events = true;
> > return IRQ_HANDLED;
> > }
> >
> > @@ -4718,6 +4723,8 @@ void dwc3_gadget_process_pending_events(struct
> > dwc3 *dwc) {
> > if (dwc->pending_events) {
> > dwc3_interrupt(dwc->irq_gadget, dwc->ev_buf);
> > + dwc3_thread_interrupt(dwc->irq_gadget, dwc->ev_buf);
> > + pm_runtime_put(dwc->dev);
> > dwc->pending_events = false;
> > enable_irq(dwc->irq_gadget);
> > }
> > --
> > 2.17.1
> >
>
> This fix is more complete.
>
> Acked-by: Thinh Nguyen <[email protected]>
>
> Thanks,
> Thinh

2023-08-02 14:47:30

by Roger Quadros

Subject: Re: [PATCH] usb: dwc3: Properly handle processing of pending events

On 01/08/2023 22:26, Elson Roy Serrao wrote:
> If dwc3 is runtime suspended we defer processing the event buffer
> until resume, by setting the pending_events flag. Set this flag before
> triggering resume to avoid race with the runtime resume callback.
>
> While handling the pending events, in addition to checking the event
> buffer we also need to process it. Handle this by explicitly calling
> dwc3_thread_interrupt(). Also balance the runtime pm get() operation
> that triggered this processing.
>
> Cc: [email protected]
> Fixes: fc8bb91bc83e ("usb: dwc3: implement runtime PM")
> Signed-off-by: Elson Roy Serrao <[email protected]>

Reviewed-by: Roger Quadros <[email protected]>

2023-08-02 14:53:02

by Roger Quadros

Subject: Re: [PATCH] usb: dwc3: Properly handle processing of pending events

Hi,

On 02/08/2023 04:39, 庞苏荣 (Surong Pang) wrote:
> Dears，
> If there is/are event(s) in evt->buf, in dwc3_check_event_buf, dwc3_thread_interrupt will be woke up.

How will it be woken up if we had disabled the IRQ to begin with?

>
>>> @@ -4718,6 +4723,8 @@ void dwc3_gadget_process_pending_events(struct
>>> dwc3 *dwc) {
>>> if (dwc->pending_events) {
>>> dwc3_interrupt(dwc->irq_gadget, dwc->ev_buf);
>>> + dwc3_thread_interrupt(dwc->irq_gadget, dwc->ev_buf);
>>> + pm_runtime_put(dwc->dev);
>>> dwc->pending_events = false;
>>> enable_irq(dwc->irq_gadget);
>>> }
>
> I just want to know dwc3_thread_interrupt here is necessary or not?
>
As IRQ was disabled, we will have to call dwc3_thread_interrupt() to
process the events that are still pending.

>
>> On Tue, Aug 02, 2023 8:12 Thinh Nguyen wrote:
>>> On Tue, Aug 01, 2023, Elson Roy Serrao wrote:
>>> If dwc3 is runtime suspended we defer processing the event buffer
>>> until resume, by setting the pending_events flag. Set this flag before
>>> triggering resume to avoid race with the runtime resume callback.
>>>
>>> While handling the pending events, in addition to checking the event
>>> buffer we also need to process it. Handle this by explicitly calling
>>> dwc3_thread_interrupt(). Also balance the runtime pm get() operation
>>> that triggered this processing.
>>>
>>> Cc: [email protected]
>>> Fixes: fc8bb91bc83e ("usb: dwc3: implement runtime PM")
>>> Signed-off-by: Elson Roy Serrao <[email protected]>
>>> ---
>>> Change separated from below series as an independent fix based on the
>>> earlier discussion
>>> https://urldefense.com/v3/__https://lore.kernel.org/all/be57511d-2005-
>>> [email protected]/__;!!A4F2R9G_pg!YtZ93ALEpDNTCEhf0WE
>>> yB5S090pPlKIKVtjqTOAEJdxdWbl8QG6eiRmlvfivUtD5qjKWWLX2C4fb4W8VAg5w9qasL
>>> uKB$
>>>
>>> drivers/usb/dwc3/gadget.c | 9 ++++++++-
>>> 1 file changed, 8 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
>>> index 5fd067151fbf..858fe4c299b7 100644
>>> --- a/drivers/usb/dwc3/gadget.c
>>> +++ b/drivers/usb/dwc3/gadget.c
>>> @@ -4455,9 +4455,14 @@ static irqreturn_t dwc3_check_event_buf(struct dwc3_event_buffer *evt)
>>> u32 count;
>>>
>>> if (pm_runtime_suspended(dwc->dev)) {
>>> + dwc->pending_events = true;
>>> + /*
>>> + * Trigger runtime resume. The get() function will be balanced
>>> + * after processing the pending events in dwc3_process_pending
>>> + * events().
>>> + */
>>> pm_runtime_get(dwc->dev);
>>> disable_irq_nosync(dwc->irq_gadget);
>>> - dwc->pending_events = true;
>>> return IRQ_HANDLED;
>>> }
>>>
>>> @@ -4718,6 +4723,8 @@ void dwc3_gadget_process_pending_events(struct
>>> dwc3 *dwc) {
>>> if (dwc->pending_events) {
>>> dwc3_interrupt(dwc->irq_gadget, dwc->ev_buf);
>>> + dwc3_thread_interrupt(dwc->irq_gadget, dwc->ev_buf);
>>> + pm_runtime_put(dwc->dev);
>>> dwc->pending_events = false;
>>> enable_irq(dwc->irq_gadget);
>>> }
>>> --
>>> 2.17.1
>>>
>>
>> This fix is more complete.
>>
>> Acked-by: Thinh Nguyen <[email protected]>
>>
>> Thanks,
>> Thinh

--
cheers,
-roger