Re: [PATCH v2] extcon: usb-gpio: Don't miss event during suspend/resume

From: Grygorii Strashko
Date: Mon Apr 11 2016 - 04:37:46 EST


On 04/11/2016 03:31 AM, Chanwoo Choi wrote:
> Hi Roger,
>
> On 2016ë 04ì 08ì 16:34, Roger Quadros wrote:
>> Pin state might have changed during suspend/resume while
>> our interrupts were disabled and if device doesn't support wakeup.
>>
>> Scan for change during resume for such case.
>>
>> Signed-off-by: Roger Quadros <rogerq@xxxxxx>
>> ---
>> v2:
>> - only check for state change during resume if device wakeup is not supported
>>
>> drivers/extcon/extcon-usb-gpio.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/extcon/extcon-usb-gpio.c b/drivers/extcon/extcon-usb-gpio.c
>> index bc61d11..118f8ab 100644
>> --- a/drivers/extcon/extcon-usb-gpio.c
>> +++ b/drivers/extcon/extcon-usb-gpio.c
>> @@ -185,6 +185,8 @@ static int usb_extcon_resume(struct device *dev)
>> int ret = 0;
>>
>> enable_irq(info->id_irq);
>> + if (!device_may_wakeup(dev))
>> + usb_extcon_detect_cable(&info->wq_detcable.work);
>
> The device_may_wakeup() check the following two states:
> - dev->power.can_wakeup - device_init_wakeup() function set the this field.
> - dev->power.wakeup - device_wakeup_enable() function set the this field.
>
> The probe function of extcon-usb-gpio.c always call the 'device_init_wakeup(dev,true).
> But, anywhere in extcon-usb-gpio.c don't handle the device_wakeup_enable() for dev->power.wakeup.


device_init_wakeup()
|-> device_wakeup_enable()

>
> In the extcon-usb-gpio.c, device_may_wakeup(dev) return always 'false'.
> If you use the only device_may_wakeup(),
> device_may_wakeup() is not able to check whether interrupt is wakeup source or not.
>

This check is correct and it also will take into account wake up settings changes
which can be made through sysfs: /sys/.../devX/power/wakeup

--
regards,
-grygorii