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SubjectRe:Re: [PATCH] Input: matrix_keypad - fix keypad does not response
At 2018-02-03 21:44:50, "Marcus Folkesson" <marcus.folkesson@gmail.com> wrote:
>> diff --git a/drivers/input/keyboard/matrix_keypad.c b/drivers/input/keyboard/matrix_keypad.c
>> index 1f316d66e6f7..13fe51824637 100644
>> --- a/drivers/input/keyboard/matrix_keypad.c
>> +++ b/drivers/input/keyboard/matrix_keypad.c
>> @@ -169,7 +169,8 @@ static void matrix_keypad_scan(struct work_struct *work)
>> /* Enable IRQs again */
>> spin_lock_irq(&keypad->lock);
>> keypad->scan_pending = false;
>> - enable_row_irqs(keypad);
>> + if (keypad->stopped == false)
>> + enable_row_irqs(keypad);
>> spin_unlock_irq(&keypad->lock);
>> }
>>
>> @@ -202,14 +203,16 @@ static int matrix_keypad_start(struct input_dev *dev)
>> {
>> struct matrix_keypad *keypad = input_get_drvdata(dev);
>>
>> + spin_lock_irq(&keypad->lock);
>> keypad->stopped = false;
>> - mb();
>>
>> /*
>> * Schedule an immediate key scan to capture current key state;
>> * columns will be activated and IRQs be enabled after the scan.
>> */
>> - schedule_delayed_work(&keypad->work, 0);
>> + if (keypad->scan_pending == false)
>> + schedule_delayed_work(&keypad->work, 0);
>> + spin_unlock_irq(&keypad->lock);
>>
>> return 0;
>> }
>> @@ -218,14 +221,17 @@ static void matrix_keypad_stop(struct input_dev *dev)
>> {
>> struct matrix_keypad *keypad = input_get_drvdata(dev);
>>
>> + spin_lock_irq(&keypad->lock);
>> keypad->stopped = true;
>> - mb();
>> - flush_work(&keypad->work.work);
>> /*
>> * matrix_keypad_scan() will leave IRQs enabled;
>> * we should disable them now.
>> */
>> - disable_row_irqs(keypad);
>> + if (keypad->scan_pending == false)
>> + disable_row_irqs(keypad);
>> + spin_unlock_irq(&keypad->lock);
>> +
>> + flush_work(&keypad->work.work);
>> }
>
>
>Hum, I think we should use spin_lock_irqsave/spin_lock_irqrestore
>instead to be on the safe side.
>I don't see how we could guarantee that irqs is allways enabled when
>calling spin_lock_irq().

spin_lock_irq and spin_unlock_irq are called in matrix_keypad_stop and matrix_keypad_start
which are in suspend and resume, they run in process context, matrix_keypad_scan runs in
worker which is in process context also.
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