Input: MT - Add in-kernel tracking
With the INPUT_MT_TRACK flag set, the function input_mt_assign_slots() can be used to match a new set of contacts against the currently used slots. The algorithm used is based on Lagrange relaxation, and performs very well in practice; slower than mtdev for a few corner cases, but faster in most commonly occuring cases. Tested-by: Benjamin Tissoires <benjamin.tissoires@enac.fr> Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
This commit is contained in:
Henrik Rydberg
parent
55e49089f4
commit
7c1a87897c
@ -46,7 +46,7 @@ int input_mt_init_slots(struct input_dev *dev, unsigned int num_slots,
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mt = kzalloc(sizeof(*mt) + num_slots * sizeof(*mt->slots), GFP_KERNEL);
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if (!mt)
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return -ENOMEM;
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goto err_mem;
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mt->num_slots = num_slots;
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mt->flags = flags;
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@ -74,6 +74,12 @@ int input_mt_init_slots(struct input_dev *dev, unsigned int num_slots,
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}
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if (flags & INPUT_MT_DIRECT)
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__set_bit(INPUT_PROP_DIRECT, dev->propbit);
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if (flags & INPUT_MT_TRACK) {
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unsigned int n2 = num_slots * num_slots;
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mt->red = kcalloc(n2, sizeof(*mt->red), GFP_KERNEL);
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if (!mt->red)
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goto err_mem;
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}
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/* Mark slots as 'unused' */
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for (i = 0; i < num_slots; i++)
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@ -81,6 +87,9 @@ int input_mt_init_slots(struct input_dev *dev, unsigned int num_slots,
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dev->mt = mt;
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return 0;
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err_mem:
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kfree(mt);
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return -ENOMEM;
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}
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EXPORT_SYMBOL(input_mt_init_slots);
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@ -93,7 +102,10 @@ EXPORT_SYMBOL(input_mt_init_slots);
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*/
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void input_mt_destroy_slots(struct input_dev *dev)
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{
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kfree(dev->mt);
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if (dev->mt) {
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kfree(dev->mt->red);
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kfree(dev->mt);
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}
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dev->mt = NULL;
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}
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EXPORT_SYMBOL(input_mt_destroy_slots);
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@ -243,3 +255,131 @@ void input_mt_sync_frame(struct input_dev *dev)
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mt->frame++;
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}
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EXPORT_SYMBOL(input_mt_sync_frame);
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static int adjust_dual(int *begin, int step, int *end, int eq)
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{
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int f, *p, s, c;
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if (begin == end)
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return 0;
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f = *begin;
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p = begin + step;
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s = p == end ? f + 1 : *p;
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for (; p != end; p += step)
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if (*p < f)
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s = f, f = *p;
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else if (*p < s)
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s = *p;
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c = (f + s + 1) / 2;
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if (c == 0 || (c > 0 && !eq))
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return 0;
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if (s < 0)
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c *= 2;
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for (p = begin; p != end; p += step)
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*p -= c;
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return (c < s && s <= 0) || (f >= 0 && f < c);
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}
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static void find_reduced_matrix(int *w, int nr, int nc, int nrc)
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{
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int i, k, sum;
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for (k = 0; k < nrc; k++) {
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for (i = 0; i < nr; i++)
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adjust_dual(w + i, nr, w + i + nrc, nr <= nc);
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sum = 0;
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for (i = 0; i < nrc; i += nr)
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sum += adjust_dual(w + i, 1, w + i + nr, nc <= nr);
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if (!sum)
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break;
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}
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}
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static int input_mt_set_matrix(struct input_mt *mt,
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const struct input_mt_pos *pos, int num_pos)
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{
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const struct input_mt_pos *p;
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struct input_mt_slot *s;
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int *w = mt->red;
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int x, y;
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for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
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if (!input_mt_is_active(s))
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continue;
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x = input_mt_get_value(s, ABS_MT_POSITION_X);
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y = input_mt_get_value(s, ABS_MT_POSITION_Y);
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for (p = pos; p != pos + num_pos; p++) {
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int dx = x - p->x, dy = y - p->y;
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*w++ = dx * dx + dy * dy;
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}
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}
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return w - mt->red;
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}
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static void input_mt_set_slots(struct input_mt *mt,
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int *slots, int num_pos)
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{
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struct input_mt_slot *s;
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int *w = mt->red, *p;
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for (p = slots; p != slots + num_pos; p++)
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*p = -1;
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for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
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if (!input_mt_is_active(s))
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continue;
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for (p = slots; p != slots + num_pos; p++)
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if (*w++ < 0)
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*p = s - mt->slots;
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}
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for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
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if (input_mt_is_active(s))
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continue;
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for (p = slots; p != slots + num_pos; p++)
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if (*p < 0) {
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*p = s - mt->slots;
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break;
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}
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}
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}
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/**
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* input_mt_assign_slots() - perform a best-match assignment
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* @dev: input device with allocated MT slots
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* @slots: the slot assignment to be filled
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* @pos: the position array to match
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* @num_pos: number of positions
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*
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* Performs a best match against the current contacts and returns
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* the slot assignment list. New contacts are assigned to unused
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* slots.
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*
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* Returns zero on success, or negative error in case of failure.
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*/
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int input_mt_assign_slots(struct input_dev *dev, int *slots,
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const struct input_mt_pos *pos, int num_pos)
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{
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struct input_mt *mt = dev->mt;
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int nrc;
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if (!mt || !mt->red)
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return -ENXIO;
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if (num_pos > mt->num_slots)
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return -EINVAL;
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if (num_pos < 1)
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return 0;
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nrc = input_mt_set_matrix(mt, pos, num_pos);
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find_reduced_matrix(mt->red, num_pos, nrc / num_pos, nrc);
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input_mt_set_slots(mt, slots, num_pos);
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return 0;
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}
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EXPORT_SYMBOL(input_mt_assign_slots);
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@ -18,6 +18,8 @@
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#define INPUT_MT_POINTER 0x0001 /* pointer device, e.g. trackpad */
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#define INPUT_MT_DIRECT 0x0002 /* direct device, e.g. touchscreen */
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#define INPUT_MT_DROP_UNUSED 0x0004 /* drop contacts not seen in frame */
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#define INPUT_MT_TRACK 0x0008 /* use in-kernel tracking */
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/**
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* struct input_mt_slot - represents the state of an input MT slot
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* @abs: holds current values of ABS_MT axes for this slot
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@ -35,6 +37,7 @@ struct input_mt_slot {
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* @slot: MT slot currently being transmitted
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* @flags: input_mt operation flags
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* @frame: increases every time input_mt_sync_frame() is called
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* @red: reduced cost matrix for in-kernel tracking
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* @slots: array of slots holding current values of tracked contacts
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*/
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struct input_mt {
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@ -43,6 +46,7 @@ struct input_mt {
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int slot;
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unsigned int flags;
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unsigned int frame;
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int *red;
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struct input_mt_slot slots[];
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};
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@ -58,6 +62,11 @@ static inline int input_mt_get_value(const struct input_mt_slot *slot,
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return slot->abs[code - ABS_MT_FIRST];
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}
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static inline bool input_mt_is_active(const struct input_mt_slot *slot)
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{
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return input_mt_get_value(slot, ABS_MT_TRACKING_ID) >= 0;
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}
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int input_mt_init_slots(struct input_dev *dev, unsigned int num_slots,
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unsigned int flags);
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void input_mt_destroy_slots(struct input_dev *dev);
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@ -90,4 +99,16 @@ void input_mt_report_pointer_emulation(struct input_dev *dev, bool use_count);
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void input_mt_sync_frame(struct input_dev *dev);
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/**
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* struct input_mt_pos - contact position
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* @x: horizontal coordinate
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* @y: vertical coordinate
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*/
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struct input_mt_pos {
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s16 x, y;
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};
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int input_mt_assign_slots(struct input_dev *dev, int *slots,
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const struct input_mt_pos *pos, int num_pos);
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#endif
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