libinput/src/evdev-fallback.h
Peter Hutterer de994d135e evdev: add new debouncing code
The current debouncing code monitors events and switches on when events are
too close together. From then on, any event can be delayed.

Vicente Bergas provided an algorithm that avoids most of these delays:
on a button state change we now forward the change without delay but start a
timer. If the button changes state during that timer, the changes are
ignored. On timer expiry, events are sent to match the hardware state
with the client's view of the device. This is only done if needed.

Thus, a press-release sequence of: PRP sends a single press event, a sequence of
PRPR sends press and then the release at the end of the timeout. The timeout
is short enough that the delay should not be noticeable.

This new mode is called the 'bounce' mode. The old mode is now referred to as
'spurious' mode and only covers the case of a button held down that loses
contact. It works as before, monitoring a button for these spurious contact
losses and switching on. When on, button release events are delayed as before.

The whole button debouncing moves to a state machine which makes debugging a
lot easier. See the accompanying SVG for the diagram.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
2017-11-20 09:55:05 +10:00

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5.7 KiB
C

/*
* Copyright © 2010 Intel Corporation
* Copyright © 2013 Jonas Ådahl
* Copyright © 2013-2017 Red Hat, Inc.
* Copyright © 2017 James Ye <jye836@gmail.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#include "config.h"
#ifndef EVDEV_FALLBACK_H
#define EVDEV_FALLBACK_H
#include "evdev.h"
enum debounce_state {
DEBOUNCE_STATE_IS_UP = 100,
DEBOUNCE_STATE_IS_DOWN,
DEBOUNCE_STATE_DOWN_WAITING,
DEBOUNCE_STATE_RELEASE_PENDING,
DEBOUNCE_STATE_RELEASE_DELAYED,
DEBOUNCE_STATE_RELEASE_WAITING,
DEBOUNCE_STATE_MAYBE_SPURIOUS,
DEBOUNCE_STATE_RELEASED,
DEBOUNCE_STATE_PRESS_PENDING,
};
struct fallback_dispatch {
struct evdev_dispatch base;
struct evdev_device *device;
struct libinput_device_config_calibration calibration;
struct {
bool is_enabled;
int angle;
struct matrix matrix;
struct libinput_device_config_rotation config;
} rotation;
struct {
struct device_coords point;
int32_t seat_slot;
} abs;
struct {
int slot;
struct mt_slot *slots;
size_t slots_len;
bool want_hysteresis;
struct device_coords hysteresis_margin;
} mt;
struct device_coords rel;
struct device_coords wheel;
struct {
/* The struct for the tablet mode switch device itself */
struct {
int state;
} sw;
/* The struct for other devices listening to the tablet mode
switch */
struct {
struct evdev_device *sw_device;
struct libinput_event_listener listener;
} other;
} tablet_mode;
/* Bitmask of pressed keys used to ignore initial release events from
* the kernel. */
unsigned long hw_key_mask[NLONGS(KEY_CNT)];
unsigned long last_hw_key_mask[NLONGS(KEY_CNT)];
enum evdev_event_type pending_event;
/* true if we're reading events (i.e. not suspended) but we're
ignoring them */
bool ignore_events;
struct {
#if 0
enum evdev_debounce_state state;
uint64_t button_up_time;
#endif
unsigned int button_code;
uint64_t button_time;
struct libinput_timer timer;
struct libinput_timer timer_short;
enum debounce_state state;
bool spurious_enabled;
} debounce;
struct {
enum switch_reliability reliability;
bool is_closed;
bool is_closed_client_state;
/* We allow up to 3 paired keyboards for the lid switch
* listener. Only one keyboard should exist, but that can
* have more than one event node.
*
* Note: this is a sparse list, any element may have a
* non-NULL device.
*/
struct paired_keyboard {
struct evdev_device *device;
struct libinput_event_listener listener;
} paired_keyboard[3];
} lid;
};
static inline struct fallback_dispatch*
fallback_dispatch(struct evdev_dispatch *dispatch)
{
evdev_verify_dispatch_type(dispatch, DISPATCH_FALLBACK);
return container_of(dispatch, struct fallback_dispatch, base);
}
enum key_type {
KEY_TYPE_NONE,
KEY_TYPE_KEY,
KEY_TYPE_BUTTON,
};
static inline enum key_type
get_key_type(uint16_t code)
{
switch (code) {
case BTN_TOOL_PEN:
case BTN_TOOL_RUBBER:
case BTN_TOOL_BRUSH:
case BTN_TOOL_PENCIL:
case BTN_TOOL_AIRBRUSH:
case BTN_TOOL_MOUSE:
case BTN_TOOL_LENS:
case BTN_TOOL_QUINTTAP:
case BTN_TOOL_DOUBLETAP:
case BTN_TOOL_TRIPLETAP:
case BTN_TOOL_QUADTAP:
case BTN_TOOL_FINGER:
case BTN_TOUCH:
return KEY_TYPE_NONE;
}
if (code >= KEY_ESC && code <= KEY_MICMUTE)
return KEY_TYPE_KEY;
if (code >= BTN_MISC && code <= BTN_GEAR_UP)
return KEY_TYPE_BUTTON;
if (code >= KEY_OK && code <= KEY_LIGHTS_TOGGLE)
return KEY_TYPE_KEY;
if (code >= BTN_DPAD_UP && code <= BTN_DPAD_RIGHT)
return KEY_TYPE_BUTTON;
if (code >= KEY_ALS_TOGGLE && code <= KEY_ONSCREEN_KEYBOARD)
return KEY_TYPE_KEY;
if (code >= BTN_TRIGGER_HAPPY && code <= BTN_TRIGGER_HAPPY40)
return KEY_TYPE_BUTTON;
return KEY_TYPE_NONE;
}
static inline void
hw_set_key_down(struct fallback_dispatch *dispatch, int code, int pressed)
{
long_set_bit_state(dispatch->hw_key_mask, code, pressed);
}
static inline bool
hw_key_has_changed(struct fallback_dispatch *dispatch, int code)
{
return long_bit_is_set(dispatch->hw_key_mask, code) !=
long_bit_is_set(dispatch->last_hw_key_mask, code);
}
static inline void
hw_key_update_last_state(struct fallback_dispatch *dispatch)
{
static_assert(sizeof(dispatch->hw_key_mask) ==
sizeof(dispatch->last_hw_key_mask),
"Mismatching key mask size");
memcpy(dispatch->last_hw_key_mask,
dispatch->hw_key_mask,
sizeof(dispatch->hw_key_mask));
}
static inline bool
hw_is_key_down(struct fallback_dispatch *dispatch, int code)
{
return long_bit_is_set(dispatch->hw_key_mask, code);
}
static inline int
get_key_down_count(struct evdev_device *device, int code)
{
return device->key_count[code];
}
void fallback_init_debounce(struct fallback_dispatch *dispatch);
void fallback_debounce_handle_state(struct fallback_dispatch *dispatch,
uint64_t time);
#endif