Re: [PATCH] Input: zforce: fix possible driver hang during suspend

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Tue, Dec 10, 2013 at 04:50:04PM +0100, Heiko Stübner wrote:
> handle_level_irq masks the interrupt before handling it, and only
> unmasks it after the handler is finished. So when a touch event
> happens after threads are suspended, but before the system is fully asleep
> the irq handler tries to wakeup the thread which will only happen on the
> next resume, resulting in the wakeup event never being sent and the driver
> not being able to wake the system from sleep due to the masked irq.
> 
> Therefore move the wakeup_event to a small non-threaded handler.
> 
> Signed-off-by: Heiko Stuebner <heiko@sntech.de>

Applied, thank you.

> ---
>  drivers/input/touchscreen/zforce_ts.c |   21 +++++++++++++++------
>  1 file changed, 15 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/input/touchscreen/zforce_ts.c b/drivers/input/touchscreen/zforce_ts.c
> index 75762d6..aa127ba 100644
> --- a/drivers/input/touchscreen/zforce_ts.c
> +++ b/drivers/input/touchscreen/zforce_ts.c
> @@ -455,7 +455,18 @@ static void zforce_complete(struct zforce_ts *ts, int cmd, int result)
>  	}
>  }
>  
> -static irqreturn_t zforce_interrupt(int irq, void *dev_id)
> +static irqreturn_t zforce_irq(int irq, void *dev_id)
> +{
> +	struct zforce_ts *ts = dev_id;
> +	struct i2c_client *client = ts->client;
> +
> +	if (ts->suspended && device_may_wakeup(&client->dev))
> +		pm_wakeup_event(&client->dev, 500);
> +
> +	return IRQ_WAKE_THREAD;
> +}
> +
> +static irqreturn_t zforce_irq_thread(int irq, void *dev_id)
>  {
>  	struct zforce_ts *ts = dev_id;
>  	struct i2c_client *client = ts->client;
> @@ -465,12 +476,10 @@ static irqreturn_t zforce_interrupt(int irq, void *dev_id)
>  	u8 *payload;
>  
>  	/*
> -	 * When suspended, emit a wakeup signal if necessary and return.
> +	 * When still suspended, return.
>  	 * Due to the level-interrupt we will get re-triggered later.
>  	 */
>  	if (ts->suspended) {
> -		if (device_may_wakeup(&client->dev))
> -			pm_wakeup_event(&client->dev, 500);
>  		msleep(20);
>  		return IRQ_HANDLED;
>  	}
> @@ -763,8 +772,8 @@ static int zforce_probe(struct i2c_client *client,
>  	 * Therefore we can trigger the interrupt anytime it is low and do
>  	 * not need to limit it to the interrupt edge.
>  	 */
> -	ret = devm_request_threaded_irq(&client->dev, client->irq, NULL,
> -					zforce_interrupt,
> +	ret = devm_request_threaded_irq(&client->dev, client->irq,
> +					zforce_irq, zforce_irq_thread,
>  					IRQF_TRIGGER_LOW | IRQF_ONESHOT,
>  					input_dev->name, ts);
>  	if (ret) {
> -- 
> 1.7.10.4
> 

-- 
Dmitry
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