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SubjectRe: [PATCH] Input: matrix_keypad - fix keypad does not response
Hi!
On Sat, Feb 03, 2018 at 08:00:46PM +0800, Zhang Bo wrote:
> From: zhangbo <zbsdta@126.com>
>
> If matrix_keypad_stop() is calling and the keypad interrupt is triggered,
> disable_row_irqs() is called by both matrix_keypad_interrupt() and
> matrix_keypad_stop() at the same time. then disable_row_irqs() is called
> twice, and the device enter suspend state before keypad->work is executed.
> At this condition the device will start keypad and enable irq once after
> resume. and then irqs are disabled yet because irqs are disabled twice and
> only enable once.
>
> Signed-off-by: zhangbo <zbsdta@126.com>

Please use your full real name in the signed-off-by tag.

> ---
> drivers/input/keyboard/matrix_keypad.c | 18 ++++++++++++------
> 1 file changed, 12 insertions(+), 6 deletions(-)
>
> 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().


>
> #ifdef CONFIG_PM_SLEEP
> --
> 2.14.3


Best regards
Marcus Folkesson
>
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