linux-kernel - Re: [PATCH] Input: only send a syn event when needed in input_dev_release

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Date:	Wed, 26 Aug 2015 13:06:03 -0700
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	Hans Holmberg <hans.holmberg@...el.com>
Cc:	ting.li@...el.com,
	"linux-input@...r.kernel.org" <linux-input@...r.kernel.org>,
	lkml <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] Input: only send a syn event when needed in input_dev_release_keys

Hi Hans,

On Wed, Aug 26, 2015 at 12:38 AM, Hans Holmberg <hans.holmberg@...el.com> wrote:
> A SYN event is reported in input_release_keys even if no keys are
> released. Stop doing this as the superfluous event can prevent autosleep
> if a user has opened a device with EPOLLWAKEUP enabled.
>
> Based on a patch developed by Ting Li <ting.li@...el.com>.
>
> Signed-off-by: Hans Holmberg <hans.holmberg@...el.com>

We already have a similar commit
00159f19a5057cb779146afce1cceede692af346 in next.

Thanks!

> ---
>  drivers/input/input.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/input/input.c b/drivers/input/input.c
> index 78d2499..c748805 100644
> --- a/drivers/input/input.c
> +++ b/drivers/input/input.c
> @@ -675,12 +675,18 @@ EXPORT_SYMBOL(input_close_device);
>  static void input_dev_release_keys(struct input_dev *dev)
>  {
>         int code;
> +       bool key_released = false;
>
>         if (is_event_supported(EV_KEY, dev->evbit, EV_MAX)) {
> -               for_each_set_bit(code, dev->key, KEY_CNT)
> +               for_each_set_bit(code, dev->key, KEY_CNT) {
>                         input_pass_event(dev, EV_KEY, code, 0);
> -               memset(dev->key, 0, sizeof(dev->key));
> -               input_pass_event(dev, EV_SYN, SYN_REPORT, 1);
> +                       key_released = true;
> +               }
> +
> +               if (key_released) {
> +                       memset(dev->key, 0, sizeof(dev->key));
> +                       input_pass_event(dev, EV_SYN, SYN_REPORT, 1);
> +               }
>         }
>  }
>
> --
> 1.9.1
>



-- 
Dmitry
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