If the device is already in the runtime suspended state, any call to
the pullup routine will issue a runtime resume on the DWC3 core
device. If the USB gadget is disabling the pullup, then avoid having
to issue a runtime resume, as DWC3 gadget has already been
halted/stopped.
This fixes an issue where the following condition occurs:
usb_gadget_remove_driver()
-->usb_gadget_disconnect()
-->dwc3_gadget_pullup(0)
-->pm_runtime_get_sync() -> ret = 0
-->pm_runtime_put() [async]
-->usb_gadget_udc_stop()
-->dwc3_gadget_stop()
-->dwc->gadget_driver = NULL
...
dwc3_suspend_common()
-->dwc3_gadget_suspend()
-->DWC3 halt/stop routine skipped, driver_data == NULL
This leads to a situation where the DWC3 gadget is not properly
stopped, as the runtime resume would have re-enabled EP0 and event
interrupts, and since we avoided the DWC3 gadget suspend, these
resources were never disabled.
Signed-off-by: Wesley Cheng <[email protected]>
---
drivers/usb/dwc3/gadget.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index a29a4ca..5d08454 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2435,6 +2435,17 @@ static int dwc3_gadget_pullup(struct usb_gadget *g, int is_on)
}
/*
+ * Avoid issuing a runtime resume if the device is already in the
+ * suspended state during gadget disconnect. DWC3 gadget was already
+ * halted/stopped during runtime suspend.
+ */
+ if (!is_on) {
+ pm_runtime_barrier(dwc->dev);
+ if (pm_runtime_suspended(dwc->dev))
+ return 0;
+ }
+
+ /*
* Check the return value for successful resume, or error. For a
* successful resume, the DWC3 runtime PM resume routine will handle
* the run stop sequence, so avoid duplicate operations here.
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
Hi Wesley,
On Fri, Jul 30, 2021 at 05:29:34PM -0700, Wesley Cheng wrote:
> If the device is already in the runtime suspended state, any call to
> the pullup routine will issue a runtime resume on the DWC3 core
> device. If the USB gadget is disabling the pullup, then avoid having
> to issue a runtime resume, as DWC3 gadget has already been
> halted/stopped.
>
> This fixes an issue where the following condition occurs:
>
> usb_gadget_remove_driver()
> -->usb_gadget_disconnect()
> -->dwc3_gadget_pullup(0)
> -->pm_runtime_get_sync() -> ret = 0
> -->pm_runtime_put() [async]
> -->usb_gadget_udc_stop()
> -->dwc3_gadget_stop()
> -->dwc->gadget_driver = NULL
> ...
>
> dwc3_suspend_common()
> -->dwc3_gadget_suspend()
> -->DWC3 halt/stop routine skipped, driver_data == NULL
>
> This leads to a situation where the DWC3 gadget is not properly
> stopped, as the runtime resume would have re-enabled EP0 and event
> interrupts, and since we avoided the DWC3 gadget suspend, these
> resources were never disabled.
>
> Signed-off-by: Wesley Cheng <[email protected]>
> ---
> drivers/usb/dwc3/gadget.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index a29a4ca..5d08454 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -2435,6 +2435,17 @@ static int dwc3_gadget_pullup(struct usb_gadget *g, int is_on)
> }
>
> /*
> + * Avoid issuing a runtime resume if the device is already in the
> + * suspended state during gadget disconnect. DWC3 gadget was already
> + * halted/stopped during runtime suspend.
> + */
> + if (!is_on) {
> + pm_runtime_barrier(dwc->dev);
> + if (pm_runtime_suspended(dwc->dev))
> + return 0;
> + }
> +
> + /*
> * Check the return value for successful resume, or error. For a
> * successful resume, the DWC3 runtime PM resume routine will handle
> * the run stop sequence, so avoid duplicate operations here.
Should this also go to stable with Fixes: 77adb8bdf422 ("usb: dwc3:
gadget: Allow runtime suspend if UDC unbinded") ?
Jack
Jack Pham <[email protected]> writes:
> Hi Wesley,
>
> On Fri, Jul 30, 2021 at 05:29:34PM -0700, Wesley Cheng wrote:
>> If the device is already in the runtime suspended state, any call to
>> the pullup routine will issue a runtime resume on the DWC3 core
>> device. If the USB gadget is disabling the pullup, then avoid having
>> to issue a runtime resume, as DWC3 gadget has already been
>> halted/stopped.
>>
>> This fixes an issue where the following condition occurs:
>>
>> usb_gadget_remove_driver()
>> -->usb_gadget_disconnect()
>> -->dwc3_gadget_pullup(0)
>> -->pm_runtime_get_sync() -> ret = 0
>> -->pm_runtime_put() [async]
>> -->usb_gadget_udc_stop()
>> -->dwc3_gadget_stop()
>> -->dwc->gadget_driver = NULL
>> ...
>>
>> dwc3_suspend_common()
>> -->dwc3_gadget_suspend()
>> -->DWC3 halt/stop routine skipped, driver_data == NULL
>>
>> This leads to a situation where the DWC3 gadget is not properly
>> stopped, as the runtime resume would have re-enabled EP0 and event
>> interrupts, and since we avoided the DWC3 gadget suspend, these
>> resources were never disabled.
>>
>> Signed-off-by: Wesley Cheng <[email protected]>
>> ---
>> drivers/usb/dwc3/gadget.c | 11 +++++++++++
>> 1 file changed, 11 insertions(+)
>>
>> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
>> index a29a4ca..5d08454 100644
>> --- a/drivers/usb/dwc3/gadget.c
>> +++ b/drivers/usb/dwc3/gadget.c
>> @@ -2435,6 +2435,17 @@ static int dwc3_gadget_pullup(struct usb_gadget *g, int is_on)
>> }
>>
>> /*
>> + * Avoid issuing a runtime resume if the device is already in the
>> + * suspended state during gadget disconnect. DWC3 gadget was already
>> + * halted/stopped during runtime suspend.
>> + */
>> + if (!is_on) {
>> + pm_runtime_barrier(dwc->dev);
>> + if (pm_runtime_suspended(dwc->dev))
>> + return 0;
>> + }
>> +
>> + /*
>> * Check the return value for successful resume, or error. For a
>> * successful resume, the DWC3 runtime PM resume routine will handle
>> * the run stop sequence, so avoid duplicate operations here.
>
> Should this also go to stable with Fixes: 77adb8bdf422 ("usb: dwc3:
> gadget: Allow runtime suspend if UDC unbinded") ?
sounds like a good idea.
--
balbi
On 8/3/2021 12:58 AM, Felipe Balbi wrote:
>
> Jack Pham <[email protected]> writes:
>
>> Hi Wesley,
>>
>> On Fri, Jul 30, 2021 at 05:29:34PM -0700, Wesley Cheng wrote:
>>> If the device is already in the runtime suspended state, any call to
>>> the pullup routine will issue a runtime resume on the DWC3 core
>>> device. If the USB gadget is disabling the pullup, then avoid having
>>> to issue a runtime resume, as DWC3 gadget has already been
>>> halted/stopped.
>>>
>>> This fixes an issue where the following condition occurs:
>>>
>>> usb_gadget_remove_driver()
>>> -->usb_gadget_disconnect()
>>> -->dwc3_gadget_pullup(0)
>>> -->pm_runtime_get_sync() -> ret = 0
>>> -->pm_runtime_put() [async]
>>> -->usb_gadget_udc_stop()
>>> -->dwc3_gadget_stop()
>>> -->dwc->gadget_driver = NULL
>>> ...
>>>
>>> dwc3_suspend_common()
>>> -->dwc3_gadget_suspend()
>>> -->DWC3 halt/stop routine skipped, driver_data == NULL
>>>
>>> This leads to a situation where the DWC3 gadget is not properly
>>> stopped, as the runtime resume would have re-enabled EP0 and event
>>> interrupts, and since we avoided the DWC3 gadget suspend, these
>>> resources were never disabled.
>>>
>>> Signed-off-by: Wesley Cheng <[email protected]>
>>> ---
>>> drivers/usb/dwc3/gadget.c | 11 +++++++++++
>>> 1 file changed, 11 insertions(+)
>>>
>>> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
>>> index a29a4ca..5d08454 100644
>>> --- a/drivers/usb/dwc3/gadget.c
>>> +++ b/drivers/usb/dwc3/gadget.c
>>> @@ -2435,6 +2435,17 @@ static int dwc3_gadget_pullup(struct usb_gadget *g, int is_on)
>>> }
>>>
>>> /*
>>> + * Avoid issuing a runtime resume if the device is already in the
>>> + * suspended state during gadget disconnect. DWC3 gadget was already
>>> + * halted/stopped during runtime suspend.
>>> + */
>>> + if (!is_on) {
>>> + pm_runtime_barrier(dwc->dev);
>>> + if (pm_runtime_suspended(dwc->dev))
>>> + return 0;
>>> + }
>>> +
>>> + /*
>>> * Check the return value for successful resume, or error. For a
>>> * successful resume, the DWC3 runtime PM resume routine will handle
>>> * the run stop sequence, so avoid duplicate operations here.
Hi Jack/Felipe,
>>
>> Should this also go to stable with Fixes: 77adb8bdf422 ("usb: dwc3:
>> gadget: Allow runtime suspend if UDC unbinded") ?
>
> sounds like a good idea.
>
Sure, will update the commit text with the fixes tag. Thanks!
Regards,
Wesley Cheng
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project