linux-kernel - Re: [PATCH v3] Input: matrix_keypad

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Date:   Mon, 5 Feb 2018 15:07:29 -0800
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Zhang Bo <zbsdta@....com>
Cc:     DRivshin@...worx.com, robh@...nel.org, linux-input@...r.kernel.org,
        linux-kernel@...r.kernel.org, zhang.bo19@....com.cn
Subject: Re: [PATCH v3] Input: matrix_keypad - fix keypad does not response

On Sun, Feb 04, 2018 at 08:19:22AM +0800, Zhang Bo wrote:
> 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.
> 
> Take lock around keypad->stopped to ensure irqs operation is in atomic
> operation.
> 
> Signed-off-by: Zhang Bo <zbsdta@....com>

Applied, thank you.

> ---
> Changes in v3:
>   - delete no needed lock protection, only add lock in matrix_keypad_stop().
> Changes in v2:
>   - Change commit message and full name in the signed-off-by tag.
> 
>  drivers/input/keyboard/matrix_keypad.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/input/keyboard/matrix_keypad.c b/drivers/input/keyboard/matrix_keypad.c
> index 1f316d66e6f7..41614c185918 100644
> --- a/drivers/input/keyboard/matrix_keypad.c
> +++ b/drivers/input/keyboard/matrix_keypad.c
> @@ -218,8 +218,10 @@ 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();
> +	spin_unlock_irq(&keypad->lock);
> +
>  	flush_work(&keypad->work.work);
>  	/*
>  	 * matrix_keypad_scan() will leave IRQs enabled;
> -- 
> 2.14.3
> 
> 

-- 
Dmitry