linux-kernel - Re: [PATCH] input: ff-memless: don't schedule already playing effect to play again

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Date:	Tue, 4 Mar 2014 09:07:32 -0800
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	Felix Rueegg <felix.rueegg@...il.com>
Cc:	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] input: ff-memless: don't schedule already playing effect
 to play again

Hi Felix,

On Sun, Mar 02, 2014 at 12:35:43PM +0100, Felix Rueegg wrote:
> When an effect with zero replay length, zero replay delay
> and zero envelope attack length is uploaded, it is played and then scheduled to play
> again one timer tick later. This triggers a warning (URB submitted while
> active) in combination with the xpad driver.
> 
> Skipping the rescheduling of this effect fixes the issue.

Won't the same issue happen if we happen to schedule a different effect
that would start at "now" time? We should not be "dropping" the new
effect, at least not in core.

It looks to me xpad.c needs [more] love.

> 
> Signed-off-by: Felix Rueegg <felix.rueegg@...il.com>
> ---
>  drivers/input/ff-memless.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/input/ff-memless.c b/drivers/input/ff-memless.c
> index 74c0d8c..2e06948 100644
> --- a/drivers/input/ff-memless.c
> +++ b/drivers/input/ff-memless.c
> @@ -139,10 +139,13 @@ static void ml_schedule_timer(struct ml_device *ml)
>  		if (!test_bit(FF_EFFECT_STARTED, &state->flags))
>  			continue;
>  
> -		if (test_bit(FF_EFFECT_PLAYING, &state->flags))
> +		if (test_bit(FF_EFFECT_PLAYING, &state->flags)) {
>  			next_at = calculate_next_time(state);
> -		else
> +			if (next_at == now)
> +				continue;
> +		} else {
>  			next_at = state->play_at;
> +		}
>  
>  		if (time_before_eq(now, next_at) &&
>  		    (++events == 1 || time_before(next_at, earliest)))
> -- 
> 1.9.0
> 

Thanks.

-- 
Dmitry
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