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Commit a274ac15 authored by Henrik Rydberg's avatar Henrik Rydberg
Browse files

Input: evdev - Add the events() callback 



By sending a full frame of events at the same time, the irqsoff
latency at heavy load is brought down from 200 us to 100 us.

Cc: Daniel Kurtz <djkurtz@chromium.org>
Tested-by: default avatarBenjamin Tissoires <benjamin.tissoires@enac.fr>
Tested-by: default avatarPing Cheng <pingc@wacom.com>
Acked-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: default avatarHenrik Rydberg <rydberg@euromail.se>
parent 4369c64c

drivers/input/evdev.c

+47 −21
Original line number Diff line number Diff line
@@ -54,16 +54,9 @@ struct evdev_client { 
static struct evdev *evdev_table[EVDEV_MINORS];

static DEFINE_MUTEX(evdev_table_mutex);



static void evdev_pass_event(struct evdev_client *client,

			     struct input_event *event,

			     ktime_t mono, ktime_t real)

static void __pass_event(struct evdev_client *client,

			 const struct input_event *event)

{

	event->time = ktime_to_timeval(client->clkid == CLOCK_MONOTONIC ?

					mono : real);



	/* Interrupts are disabled, just acquire the lock. */

	spin_lock(&client->buffer_lock);



	client->buffer[client->head++] = *event;

	client->head &= client->bufsize - 1;
@@ -86,42 +79,74 @@ static void evdev_pass_event(struct evdev_client *client, 
		client->packet_head = client->head;

		kill_fasync(&client->fasync, SIGIO, POLL_IN);

	}

}



static void evdev_pass_values(struct evdev_client *client,

			const struct input_value *vals, unsigned int count,

			ktime_t mono, ktime_t real)

{

	struct evdev *evdev = client->evdev;

	const struct input_value *v;

	struct input_event event;

	bool wakeup = false;



	event.time = ktime_to_timeval(client->clkid == CLOCK_MONOTONIC ?

				      mono : real);



	/* Interrupts are disabled, just acquire the lock. */

	spin_lock(&client->buffer_lock);



	for (v = vals; v != vals + count; v++) {

		event.type = v->type;

		event.code = v->code;

		event.value = v->value;

		__pass_event(client, &event);

		if (v->type == EV_SYN && v->code == SYN_REPORT)

			wakeup = true;

	}



	spin_unlock(&client->buffer_lock);



	if (wakeup)

		wake_up_interruptible(&evdev->wait);

}



/*

 * Pass incoming event to all connected clients.

 * Pass incoming events to all connected clients.

 */

static void evdev_event(struct input_handle *handle,

			unsigned int type, unsigned int code, int value)

static void evdev_events(struct input_handle *handle,

			 const struct input_value *vals, unsigned int count)

{

	struct evdev *evdev = handle->private;

	struct evdev_client *client;

	struct input_event event;

	ktime_t time_mono, time_real;



	time_mono = ktime_get();

	time_real = ktime_sub(time_mono, ktime_get_monotonic_offset());



	event.type = type;

	event.code = code;

	event.value = value;



	rcu_read_lock();



	client = rcu_dereference(evdev->grab);



	if (client)

		evdev_pass_event(client, &event, time_mono, time_real);

		evdev_pass_values(client, vals, count, time_mono, time_real);

	else

		list_for_each_entry_rcu(client, &evdev->client_list, node)

			evdev_pass_event(client, &event, time_mono, time_real);

			evdev_pass_values(client, vals, count,

					  time_mono, time_real);



	rcu_read_unlock();

}



	if (type == EV_SYN && code == SYN_REPORT)

		wake_up_interruptible(&evdev->wait);

/*

 * Pass incoming event to all connected clients.

 */

static void evdev_event(struct input_handle *handle,

			unsigned int type, unsigned int code, int value)

{

	struct input_value vals[] = { { type, code, value } };



	evdev_events(handle, vals, 1);

}



static int evdev_fasync(int fd, struct file *file, int on)
@@ -1050,6 +1075,7 @@ MODULE_DEVICE_TABLE(input, evdev_ids); 


static struct input_handler evdev_handler = {

	.event		= evdev_event,

	.events		= evdev_events,

	.connect	= evdev_connect,

	.disconnect	= evdev_disconnect,

	.fops		= &evdev_fops,