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

[Henrik Rydberg]

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@xxxxxxxxx>
Signed-off-by: Henrik Rydberg <rydberg@xxxxxxxxxxx>
---
 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

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