xref: /freebsd/sys/dev/evdev/evdev_mt.c (revision 3332f1b444d4a73238e9f59cca27bfc95fe936bd)
1 /*-
2  * Copyright (c) 2016, 2020 Vladimir Kondratyev <wulf@FreeBSD.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  * $FreeBSD$
27  */
28 /*-
29  * Copyright (c) 2015, 2016 Ulf Brosziewski
30  *
31  * Permission to use, copy, modify, and distribute this software for any
32  * purpose with or without fee is hereby granted, provided that the above
33  * copyright notice and this permission notice appear in all copies.
34  *
35  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
36  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
37  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
38  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
39  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
40  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
41  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
42  */
43 
44 #include <sys/param.h>
45 #include <sys/lock.h>
46 #include <sys/malloc.h>
47 #include <sys/mutex.h>
48 #include <sys/systm.h>
49 
50 #include <dev/evdev/evdev.h>
51 #include <dev/evdev/evdev_private.h>
52 #include <dev/evdev/input.h>
53 
54 #ifdef DEBUG
55 #define	debugf(fmt, args...)	printf("evdev: " fmt "\n", ##args)
56 #else
57 #define	debugf(fmt, args...)
58 #endif
59 
60 typedef	u_int	slotset_t;
61 
62 _Static_assert(MAX_MT_SLOTS < sizeof(slotset_t) * 8, "MAX_MT_SLOTS too big");
63 
64 #define FOREACHBIT(v, i) \
65 	for ((i) = ffs(v) - 1; (i) != -1; (i) = ffs((v) & (~1 << (i))) - 1)
66 
67 struct {
68 	uint16_t	mt;
69 	uint16_t	st;
70 	int32_t		max;
71 } static evdev_mtstmap[] = {
72 	{ ABS_MT_POSITION_X,	ABS_X,		0 },
73 	{ ABS_MT_POSITION_Y,	ABS_Y,		0 },
74 	{ ABS_MT_PRESSURE,	ABS_PRESSURE,	255 },
75 	{ ABS_MT_TOUCH_MAJOR,	ABS_TOOL_WIDTH,	15 },
76 };
77 
78 struct evdev_mt {
79 	int			last_reported_slot;
80 	uint16_t		tracking_id;
81 	int32_t			tracking_ids[MAX_MT_SLOTS];
82 	bool			type_a;
83 	u_int			mtst_events;
84 	/* the set of slots with active touches */
85 	slotset_t		touches;
86 	/* the set of slots with unsynchronized state */
87 	slotset_t		frame;
88 	/* the set of slots to match with active touches */
89 	slotset_t		match_frame;
90 	int			match_slot;
91 	union evdev_mt_slot	*match_slots;
92 	int			*matrix;
93 	union evdev_mt_slot	slots[];
94 };
95 
96 static void	evdev_mt_support_st_compat(struct evdev_dev *);
97 static void	evdev_mt_send_st_compat(struct evdev_dev *);
98 static void	evdev_mt_send_autorel(struct evdev_dev *);
99 static void	evdev_mt_replay_events(struct evdev_dev *);
100 
101 static inline int
102 ffc_slot(struct evdev_dev *evdev, slotset_t slots)
103 {
104 	return (ffs(~slots & ((2U << MAXIMAL_MT_SLOT(evdev)) - 1)) - 1);
105 }
106 
107 void
108 evdev_mt_init(struct evdev_dev *evdev)
109 {
110 	struct evdev_mt *mt;
111 	size_t size = offsetof(struct evdev_mt, slots);
112 	int slot, slots;
113 	bool type_a;
114 
115 	type_a = !bit_test(evdev->ev_abs_flags, ABS_MT_SLOT);
116 	if (type_a) {
117 		/* Add events produced by MT type A to type B converter */
118 		evdev_support_abs(evdev,
119 		    ABS_MT_SLOT, 0, MAX_MT_SLOTS - 1, 0, 0, 0);
120 		evdev_support_abs(evdev,
121 		    ABS_MT_TRACKING_ID, -1, MAX_MT_SLOTS - 1, 0, 0, 0);
122 	}
123 
124 	slots = MAXIMAL_MT_SLOT(evdev) + 1;
125 	size += sizeof(mt->slots[0]) * slots;
126 	if (bit_test(evdev->ev_flags, EVDEV_FLAG_MT_TRACK)) {
127 		size += sizeof(mt->match_slots[0]) * slots;
128 		size += sizeof(mt->matrix[0]) * (slots + 6) * slots;
129 	}
130 
131 	mt = malloc(size, M_EVDEV, M_WAITOK | M_ZERO);
132 	evdev->ev_mt = mt;
133 	mt->type_a = type_a;
134 
135 	if (bit_test(evdev->ev_flags, EVDEV_FLAG_MT_TRACK)) {
136 		mt->match_slots = mt->slots + slots;
137 		mt->matrix = (int *)(mt->match_slots + slots);
138 	}
139 
140 	/* Initialize multitouch protocol type B states */
141 	for (slot = 0; slot < slots; slot++)
142 		mt->slots[slot].id = -1;
143 
144 	if (!bit_test(evdev->ev_flags, EVDEV_FLAG_MT_KEEPID))
145 		evdev_support_abs(evdev,
146 		    ABS_MT_TRACKING_ID, -1, UINT16_MAX, 0, 0, 0);
147 	if (bit_test(evdev->ev_flags, EVDEV_FLAG_MT_STCOMPAT))
148 		evdev_mt_support_st_compat(evdev);
149 }
150 
151 void
152 evdev_mt_free(struct evdev_dev *evdev)
153 {
154 	free(evdev->ev_mt, M_EVDEV);
155 }
156 
157 void
158 evdev_mt_sync_frame(struct evdev_dev *evdev)
159 {
160 	if (bit_test(evdev->ev_flags, EVDEV_FLAG_MT_TRACK))
161 		evdev_mt_replay_events(evdev);
162 	if (bit_test(evdev->ev_flags, EVDEV_FLAG_MT_AUTOREL))
163 		evdev_mt_send_autorel(evdev);
164 	if (evdev->ev_report_opened &&
165 	    bit_test(evdev->ev_flags, EVDEV_FLAG_MT_STCOMPAT))
166 		evdev_mt_send_st_compat(evdev);
167 	evdev->ev_mt->frame = 0;
168 }
169 
170 static void
171 evdev_mt_send_slot(struct evdev_dev *evdev, int slot,
172     union evdev_mt_slot *state)
173 {
174 	int i;
175 	bool type_a = !bit_test(evdev->ev_abs_flags, ABS_MT_SLOT);
176 
177 	EVDEV_LOCK_ASSERT(evdev);
178 	MPASS(type_a || (slot >= 0 && slot <= MAXIMAL_MT_SLOT(evdev)));
179 	MPASS(!type_a || state != NULL);
180 
181 	if (!type_a) {
182 		evdev_send_event(evdev, EV_ABS, ABS_MT_SLOT, slot);
183 		if (state == NULL) {
184 			evdev_send_event(evdev, EV_ABS, ABS_MT_TRACKING_ID, -1);
185 			return;
186 		}
187 	}
188 	bit_foreach_at(evdev->ev_abs_flags, ABS_MT_FIRST, ABS_MT_LAST + 1, i)
189 		evdev_send_event(evdev, EV_ABS, i,
190 		    state->val[ABS_MT_INDEX(i)]);
191 	if (type_a)
192 		evdev_send_event(evdev, EV_SYN, SYN_MT_REPORT, 1);
193 }
194 
195 int
196 evdev_mt_push_slot(struct evdev_dev *evdev, int slot,
197     union evdev_mt_slot *state)
198 {
199 	struct evdev_mt *mt = evdev->ev_mt;
200 	bool type_a = !bit_test(evdev->ev_abs_flags, ABS_MT_SLOT);
201 
202 	if ((type_a || (mt != NULL && mt->type_a)) && state == NULL)
203 		return (EINVAL);
204 	if (!type_a && (slot < 0 || slot > MAXIMAL_MT_SLOT(evdev)))
205 		return (EINVAL);
206 
207 	EVDEV_ENTER(evdev);
208 	if (bit_test(evdev->ev_flags, EVDEV_FLAG_MT_TRACK) && mt->type_a) {
209 		mt->match_slots[mt->match_slot] = *state;
210 		evdev_mt_record_event(evdev, EV_SYN, SYN_MT_REPORT, 1);
211 	} else if (bit_test(evdev->ev_flags, EVDEV_FLAG_MT_TRACK)) {
212 		evdev_mt_record_event(evdev, EV_ABS, ABS_MT_SLOT, slot);
213 		if (state != NULL)
214 			mt->match_slots[mt->match_slot] = *state;
215 		else
216 			evdev_mt_record_event(evdev, EV_ABS,
217 			    ABS_MT_TRACKING_ID, -1);
218 	} else
219 		evdev_mt_send_slot(evdev, slot, state);
220 	EVDEV_EXIT(evdev);
221 
222 	return (0);
223 }
224 
225 /*
226  * Find a minimum-weight matching for an m-by-n matrix.
227  *
228  * m must be greater than or equal to n. The size of the buffer must be
229  * at least 3m + 3n.
230  *
231  * On return, the first m elements of the buffer contain the row-to-
232  * column mappings, i.e., buffer[i] is the column index for row i, or -1
233  * if there is no assignment for that row (which may happen if n < m).
234  *
235  * Wrong results because of overflows will not occur with input values
236  * in the range of 0 to INT_MAX / 2 inclusive.
237  *
238  * The function applies the Dinic-Kronrod algorithm. It is not modern or
239  * popular, but it seems to be a good choice for small matrices at least.
240  * The original form of the algorithm is modified as follows: There is no
241  * initial search for row minima, the initial assignments are in a
242  * "virtual" column with the index -1 and zero values. This permits inputs
243  * with n < m, and it simplifies the reassignments.
244  */
245 static void
246 evdev_mt_matching(int *matrix, int m, int n, int *buffer)
247 {
248 	int i, j, k, d, e, row, col, delta;
249 	int *p;
250 	int *r2c = buffer;	/* row-to-column assignments */
251 	int *red = r2c + m;	/* reduced values of the assignments */
252 	int *mc = red + m;	/* row-wise minimal elements of cs */
253 	int *cs = mc + m;	/* the column set */
254 	int *c2r = cs + n;	/* column-to-row assignments in cs */
255 	int *cd = c2r + n;	/* column deltas (reduction) */
256 
257 	for (p = r2c; p < red; *p++ = -1) {}
258 	for (; p < mc; *p++ = 0) {}
259 	for (col = 0; col < n; col++) {
260 		delta = INT_MAX;
261 		for (i = 0, p = matrix + col; i < m; i++, p += n) {
262 			d = *p - red[i];
263 			if (d < delta || (d == delta && r2c[i] < 0)) {
264 				delta = d;
265 				row = i;
266 			}
267 		}
268 		cd[col] = delta;
269 		if (r2c[row] < 0) {
270 			r2c[row] = col;
271 			continue;
272 		}
273 		for (p = mc; p < cs; *p++ = col) {}
274 		for (k = 0; (j = r2c[row]) >= 0;) {
275 			cs[k++] = j;
276 			c2r[j] = row;
277 			mc[row] -= n;
278 			delta = INT_MAX;
279 			for (i = 0, p = matrix; i < m; i++, p += n)
280 				if (mc[i] >= 0) {
281 					d = p[mc[i]] - cd[mc[i]];
282 					e = p[j] - cd[j];
283 					if (e < d) {
284 						d = e;
285 						mc[i] = j;
286 					}
287 					d -= red[i];
288 					if (d < delta || (d == delta
289 					    && r2c[i] < 0)) {
290 						delta = d;
291 						row = i;
292 					}
293 				}
294 			cd[col] += delta;
295 			for (i = 0; i < k; i++) {
296 				cd[cs[i]] += delta;
297 				red[c2r[cs[i]]] -= delta;
298 			}
299 		}
300 		for (j = mc[row]; (r2c[row] = j) != col;) {
301 			row = c2r[j];
302 			j = mc[row] + n;
303 		}
304 	}
305 }
306 
307 /*
308  * Assign tracking IDs to the points in the pt array.  The tracking ID
309  * assignment pairs the points with points of the previous frame in
310  * such a way that the sum of the squared distances is minimal.  Using
311  * squares instead of simple distances favours assignments with more uniform
312  * distances, and it is faster.
313  * Set tracking id to -1 for unassigned (new) points.
314  */
315 void
316 evdev_mt_match_frame(struct evdev_dev *evdev, union evdev_mt_slot *pt,
317     int size)
318 {
319 	struct evdev_mt *mt = evdev->ev_mt;
320 	int i, j, m, n, dx, dy, slot, num_touches;
321 	int *p, *r2c, *c2r;
322 
323 	EVDEV_LOCK_ASSERT(evdev);
324 	MPASS(mt->matrix != NULL);
325 	MPASS(size >= 0 && size <= MAXIMAL_MT_SLOT(evdev) + 1);
326 
327 	if (size == 0)
328 		return;
329 
330 	p = mt->matrix;
331 	num_touches = bitcount(mt->touches);
332 	if (num_touches >= size) {
333 		FOREACHBIT(mt->touches, slot)
334 			for (i = 0; i < size; i++) {
335 				dx = pt[i].x - mt->slots[slot].x;
336 				dy = pt[i].y - mt->slots[slot].y;
337 				*p++ = dx * dx + dy * dy;
338 			}
339 		m = num_touches;
340 		n = size;
341 	} else {
342 		for (i = 0; i < size; i++)
343 			FOREACHBIT(mt->touches, slot) {
344 				dx = pt[i].x - mt->slots[slot].x;
345 				dy = pt[i].y - mt->slots[slot].y;
346 				*p++ = dx * dx + dy * dy;
347 			}
348 		m = size;
349 		n = num_touches;
350 	}
351 	evdev_mt_matching(mt->matrix, m, n, p);
352 
353 	r2c = p;
354 	c2r = p + m;
355 	for (i = 0; i < m; i++)
356 		if ((j = r2c[i]) >= 0)
357 			c2r[j] = i;
358 
359 	p = (n == size ? c2r : r2c);
360 	for (i = 0; i < size; i++)
361 		if (*p++ < 0)
362 			pt[i].id = -1;
363 
364 	p = (n == size ? r2c : c2r);
365 	FOREACHBIT(mt->touches, slot)
366 		if ((i = *p++) >= 0)
367 			pt[i].id = mt->tracking_ids[slot];
368 }
369 
370 static void
371 evdev_mt_send_frame(struct evdev_dev *evdev, union evdev_mt_slot *pt, int size)
372 {
373 	struct evdev_mt *mt = evdev->ev_mt;
374 	union evdev_mt_slot *slot;
375 
376 	EVDEV_LOCK_ASSERT(evdev);
377 	MPASS(size >= 0 && size <= MAXIMAL_MT_SLOT(evdev) + 1);
378 
379 	/*
380 	 * While MT-matching assign tracking IDs of new contacts to be equal
381 	 * to a slot number to make things simpler.
382 	 */
383 	for (slot = pt; slot < pt + size; slot++) {
384 		if (slot->id < 0)
385 			slot->id = ffc_slot(evdev, mt->touches | mt->frame);
386 		if (slot->id >= 0)
387 			evdev_mt_send_slot(evdev, slot->id, slot);
388 	}
389 }
390 
391 int
392 evdev_mt_push_frame(struct evdev_dev *evdev, union evdev_mt_slot *pt, int size)
393 {
394 	if (size < 0 || size > MAXIMAL_MT_SLOT(evdev) + 1)
395 		return (EINVAL);
396 
397 	EVDEV_ENTER(evdev);
398 	evdev_mt_send_frame(evdev, pt, size);
399 	EVDEV_EXIT(evdev);
400 
401 	return (0);
402 }
403 
404 bool
405 evdev_mt_record_event(struct evdev_dev *evdev, uint16_t type, uint16_t code,
406     int32_t value)
407 {
408 	struct evdev_mt *mt = evdev->ev_mt;
409 
410 	EVDEV_LOCK_ASSERT(evdev);
411 
412 	switch (type) {
413 	case EV_SYN:
414 		if (code == SYN_MT_REPORT) {
415 			/* MT protocol type A support */
416 			KASSERT(mt->type_a, ("Not a MT type A protocol"));
417 			mt->match_frame |= 1U << mt->match_slot;
418 			mt->match_slot++;
419 			return (true);
420 		}
421 		break;
422 	case EV_ABS:
423 		if (code == ABS_MT_SLOT) {
424 			/* MT protocol type B support */
425 			KASSERT(!mt->type_a, ("Not a MT type B protocol"));
426 			KASSERT(value >= 0, ("Negative slot number"));
427 			mt->match_slot = value;
428 			mt->match_frame |= 1U << mt->match_slot;
429 			return (true);
430 		} else if (code == ABS_MT_TRACKING_ID) {
431 			KASSERT(!mt->type_a, ("Not a MT type B protocol"));
432 			if (value == -1)
433 				mt->match_frame &= ~(1U << mt->match_slot);
434 			return (true);
435 		} else if (ABS_IS_MT(code)) {
436 			KASSERT(mt->match_slot >= 0, ("Negative slot"));
437 			KASSERT(mt->match_slot <= MAXIMAL_MT_SLOT(evdev),
438 			    ("Slot number too big"));
439 			mt->match_slots[mt->match_slot].
440 			    val[ABS_MT_INDEX(code)] = value;
441 			return (true);
442 		}
443 		break;
444 	default:
445 		break;
446 	}
447 
448 	return (false);
449 }
450 
451 static void
452 evdev_mt_replay_events(struct evdev_dev *evdev)
453 {
454 	struct evdev_mt *mt = evdev->ev_mt;
455 	int slot, size = 0;
456 
457 	EVDEV_LOCK_ASSERT(evdev);
458 
459 	FOREACHBIT(mt->match_frame, slot) {
460 		if (slot != size)
461 			mt->match_slots[size] = mt->match_slots[slot];
462 		size++;
463 	}
464 	evdev_mt_match_frame(evdev, mt->match_slots, size);
465 	evdev_mt_send_frame(evdev, mt->match_slots, size);
466 	mt->match_slot = 0;
467 	mt->match_frame = 0;
468 }
469 
470 union evdev_mt_slot *
471 evdev_mt_get_match_slots(struct evdev_dev *evdev)
472 {
473 	return (evdev->ev_mt->match_slots);
474 }
475 
476 int
477 evdev_mt_get_last_slot(struct evdev_dev *evdev)
478 {
479 	return (evdev->ev_mt->last_reported_slot);
480 }
481 
482 void
483 evdev_mt_set_last_slot(struct evdev_dev *evdev, int slot)
484 {
485 	struct evdev_mt *mt = evdev->ev_mt;
486 
487 	MPASS(slot >= 0 && slot <= MAXIMAL_MT_SLOT(evdev));
488 
489 	mt->frame |= 1U << slot;
490 	mt->last_reported_slot = slot;
491 }
492 
493 int32_t
494 evdev_mt_get_value(struct evdev_dev *evdev, int slot, int16_t code)
495 {
496 	struct evdev_mt *mt = evdev->ev_mt;
497 
498 	MPASS(slot >= 0 && slot <= MAXIMAL_MT_SLOT(evdev));
499 
500 	return (mt->slots[slot].val[ABS_MT_INDEX(code)]);
501 }
502 
503 void
504 evdev_mt_set_value(struct evdev_dev *evdev, int slot, int16_t code,
505     int32_t value)
506 {
507 	struct evdev_mt *mt = evdev->ev_mt;
508 
509 	MPASS(slot >= 0 && slot <= MAXIMAL_MT_SLOT(evdev));
510 
511 	if (code == ABS_MT_TRACKING_ID) {
512 		if (value != -1)
513 			mt->touches |= 1U << slot;
514 		else
515 			mt->touches &= ~(1U << slot);
516 	}
517 	mt->slots[slot].val[ABS_MT_INDEX(code)] = value;
518 }
519 
520 int
521 evdev_mt_id_to_slot(struct evdev_dev *evdev, int32_t tracking_id)
522 {
523 	struct evdev_mt *mt = evdev->ev_mt;
524 	int slot;
525 
526 	KASSERT(!mt->type_a, ("Not a MT type B protocol"));
527 
528 	/*
529 	 * Ignore tracking_id if slot assignment is performed by evdev.
530 	 * Events are written sequentially to temporary matching buffer.
531 	 */
532 	if (bit_test(evdev->ev_flags, EVDEV_FLAG_MT_TRACK))
533 		return (ffc_slot(evdev, mt->match_frame));
534 
535 	FOREACHBIT(mt->touches, slot)
536 		if (mt->tracking_ids[slot] == tracking_id)
537 			return (slot);
538 	/*
539 	 * Do not allow allocation of new slot in a place of just
540 	 * released one within the same report.
541 	 */
542 	return (ffc_slot(evdev, mt->touches | mt->frame));
543 }
544 
545 int32_t
546 evdev_mt_reassign_id(struct evdev_dev *evdev, int slot, int32_t id)
547 {
548 	struct evdev_mt *mt = evdev->ev_mt;
549 	int32_t nid;
550 
551 	if (id == -1 || bit_test(evdev->ev_flags, EVDEV_FLAG_MT_KEEPID)) {
552 		mt->tracking_ids[slot] = id;
553 		return (id);
554 	}
555 
556 	nid = evdev_mt_get_value(evdev, slot, ABS_MT_TRACKING_ID);
557 	if (nid != -1) {
558 		KASSERT(id == mt->tracking_ids[slot],
559 		    ("MT-slot tracking id has changed"));
560 		return (nid);
561 	}
562 
563 	mt->tracking_ids[slot] = id;
564 again:
565 	nid = mt->tracking_id++;
566 	FOREACHBIT(mt->touches, slot)
567 		if (evdev_mt_get_value(evdev, slot, ABS_MT_TRACKING_ID) == nid)
568 			goto again;
569 
570 	return (nid);
571 }
572 
573 static inline int32_t
574 evdev_mt_normalize(int32_t value, int32_t mtmin, int32_t mtmax, int32_t stmax)
575 {
576 	if (stmax != 0 && mtmax != mtmin) {
577 		value = (value - mtmin) * stmax / (mtmax - mtmin);
578 		value = MAX(MIN(value, stmax), 0);
579 	}
580 	return (value);
581 }
582 
583 static void
584 evdev_mt_support_st_compat(struct evdev_dev *evdev)
585 {
586 	struct input_absinfo *ai;
587 	int i;
588 
589 	if (evdev->ev_absinfo == NULL)
590 		return;
591 
592 	evdev_support_event(evdev, EV_KEY);
593 	evdev_support_key(evdev, BTN_TOUCH);
594 
595 	/* Touchscreens should not advertise tap tool capabilities */
596 	if (!bit_test(evdev->ev_prop_flags, INPUT_PROP_DIRECT))
597 		evdev_support_nfingers(evdev, MAXIMAL_MT_SLOT(evdev) + 1);
598 
599 	/* Echo 0-th MT-slot as ST-slot */
600 	for (i = 0; i < nitems(evdev_mtstmap); i++) {
601 		if (!bit_test(evdev->ev_abs_flags, evdev_mtstmap[i].mt) ||
602 		     bit_test(evdev->ev_abs_flags, evdev_mtstmap[i].st))
603 			continue;
604 		ai = evdev->ev_absinfo + evdev_mtstmap[i].mt;
605 		evdev->ev_mt->mtst_events |= 1U << i;
606 		if (evdev_mtstmap[i].max != 0)
607 			evdev_support_abs(evdev, evdev_mtstmap[i].st,
608 			    0,
609 			    evdev_mtstmap[i].max,
610 			    0,
611 			    evdev_mt_normalize(
612 			      ai->flat, 0, ai->maximum, evdev_mtstmap[i].max),
613 			    0);
614 		else
615 			evdev_support_abs(evdev, evdev_mtstmap[i].st,
616 			    ai->minimum,
617 			    ai->maximum,
618 			    0,
619 			    ai->flat,
620 			    ai->resolution);
621 	}
622 }
623 
624 static void
625 evdev_mt_send_st_compat(struct evdev_dev *evdev)
626 {
627 	struct evdev_mt *mt = evdev->ev_mt;
628 	int nfingers, i, st_slot;
629 
630 	EVDEV_LOCK_ASSERT(evdev);
631 
632 	nfingers = bitcount(mt->touches);
633 	evdev_send_event(evdev, EV_KEY, BTN_TOUCH, nfingers > 0);
634 
635 	/* Send first active MT-slot state as single touch report */
636 	st_slot = ffs(mt->touches) - 1;
637 	if (st_slot != -1)
638 		FOREACHBIT(mt->mtst_events, i)
639 			evdev_send_event(evdev, EV_ABS, evdev_mtstmap[i].st,
640 			    evdev_mt_normalize(evdev_mt_get_value(evdev,
641 			      st_slot, evdev_mtstmap[i].mt),
642 			      evdev->ev_absinfo[evdev_mtstmap[i].mt].minimum,
643 			      evdev->ev_absinfo[evdev_mtstmap[i].mt].maximum,
644 			      evdev_mtstmap[i].max));
645 
646 	/* Touchscreens should not report tool taps */
647 	if (!bit_test(evdev->ev_prop_flags, INPUT_PROP_DIRECT))
648 		evdev_send_nfingers(evdev, nfingers);
649 
650 	if (nfingers == 0)
651 		evdev_send_event(evdev, EV_ABS, ABS_PRESSURE, 0);
652 }
653 
654 static void
655 evdev_mt_send_autorel(struct evdev_dev *evdev)
656 {
657 	struct evdev_mt *mt = evdev->ev_mt;
658 	int slot;
659 
660 	EVDEV_LOCK_ASSERT(evdev);
661 	KASSERT(mt->match_frame == 0, ("Unmatched events exist"));
662 
663 	FOREACHBIT(mt->touches & ~mt->frame, slot)
664 		evdev_mt_send_slot(evdev, slot, NULL);
665 }
666 
667 void
668 evdev_mt_push_autorel(struct evdev_dev *evdev)
669 {
670 	EVDEV_ENTER(evdev);
671 	evdev_mt_send_autorel(evdev);
672 	EVDEV_EXIT(evdev);
673 }
674