linux-kernel - Re: [PATCH v3 02/20] Input: Improve the events-per-packet estimate

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Date:	Wed, 12 Sep 2012 22:16:15 -0700
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	Henrik Rydberg <rydberg@...omail.se>
Cc:	Jiri Kosina <jkosina@...e.cz>, linux-input@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 02/20] Input: Improve the events-per-packet estimate

On Sat, Sep 01, 2012 at 09:46:57PM +0200, Henrik Rydberg wrote:
> The events-per-packet estimate has so far been used by MT devices
> only. This patch adjusts the packet buffer size to also accomodate the
> KEY and MSC events.  Keyboards normally send one or two keys at a
> time. MT devices normally send a number of button keys along with the
> MT information.  The buffer size chosen here covers those cases, and
> matches the default buffer size in evdev. Since the input estimate is
> now preferred, remove the special input-mt estimate.
> 
> Reviewed-by: Ping Cheng <pingc@...om.com>
> Signed-off-by: Henrik Rydberg <rydberg@...omail.se>

Makes sense.

Acked-by: Dmitry Torokhov <dmitry.torokhov@...il.com>

> ---
>  drivers/input/input-mt.c |  1 -
>  drivers/input/input.c    | 10 +++++++---
>  2 files changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/input/input-mt.c b/drivers/input/input-mt.c
> index c6df704..58bde77 100644
> --- a/drivers/input/input-mt.c
> +++ b/drivers/input/input-mt.c
> @@ -42,7 +42,6 @@ int input_mt_init_slots(struct input_dev *dev, unsigned int num_slots)
>  	mt->num_slots = num_slots;
>  	input_set_abs_params(dev, ABS_MT_SLOT, 0, num_slots - 1, 0, 0);
>  	input_set_abs_params(dev, ABS_MT_TRACKING_ID, 0, TRKID_MAX, 0, 0);
> -	input_set_events_per_packet(dev, 6 * num_slots);
>  
>  	/* Mark slots as 'unused' */
>  	for (i = 0; i < num_slots; i++)
> diff --git a/drivers/input/input.c b/drivers/input/input.c
> index 6e90705..8ebf116 100644
> --- a/drivers/input/input.c
> +++ b/drivers/input/input.c
> @@ -1777,6 +1777,9 @@ static unsigned int input_estimate_events_per_packet(struct input_dev *dev)
>  		if (test_bit(i, dev->relbit))
>  			events++;
>  
> +	/* Make room for KEY and MSC events */
> +	events += 7;
> +
>  	return events;
>  }
>  
> @@ -1815,6 +1818,7 @@ int input_register_device(struct input_dev *dev)
>  {
>  	static atomic_t input_no = ATOMIC_INIT(0);
>  	struct input_handler *handler;
> +	unsigned int packet_size;
>  	const char *path;
>  	int error;
>  
> @@ -1827,9 +1831,9 @@ int input_register_device(struct input_dev *dev)
>  	/* Make sure that bitmasks not mentioned in dev->evbit are clean. */
>  	input_cleanse_bitmasks(dev);
>  
> -	if (!dev->hint_events_per_packet)
> -		dev->hint_events_per_packet =
> -				input_estimate_events_per_packet(dev);
> +	packet_size = input_estimate_events_per_packet(dev);
> +	if (dev->hint_events_per_packet < packet_size)
> +		dev->hint_events_per_packet = packet_size;
>  
>  	/*
>  	 * If delay and period are pre-set by the driver, then autorepeating
> -- 
> 1.7.12
> 

-- 
Dmitry
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