Commit 1d958c83 authored by Henrik Rydberg's avatar Henrik Rydberg Committed by Jiri Kosina
Browse files

HID: 3m: Correct touchscreen emulation 



The current code sometimes misses to report the last BTN_TOUCH event
when multiple fingers are lifted simultaneously.  With the
introduction of MT slots, the tracking id is available to determine
the oldest active contact. Use this information to simplify and
correct the touchscreen emulation logic.

Signed-off-by: default avatarHenrik Rydberg <rydberg@euromail.se>
Acked-by: default avatarStéphane Chatty <chatty@enac.fr>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
parent 1f01a1fe

drivers/hid/hid-3m-pct.c

+5 −36
Original line number Diff line number Diff line
@@ -37,7 +37,6 @@ MODULE_LICENSE("GPL"); 
struct mmm_finger {

	__s32 x, y, w, h;

	__u16 id;

	__u8 rank;

	bool prev_touch;

	bool touch, valid;

};
@@ -45,7 +44,7 @@ struct mmm_finger { 
struct mmm_data {

	struct mmm_finger f[MAX_SLOTS];

	__u16 id;

	__u8 curid, num;

	__u8 curid;

	__u8 nexp, nreal;

	bool touch, valid;

};
@@ -156,13 +155,7 @@ static int mmm_input_mapped(struct hid_device *hdev, struct hid_input *hi, 
static void mmm_filter_event(struct mmm_data *md, struct input_dev *input)

{

	struct mmm_finger *oldest = 0;

	bool pressed = false, released = false;

	int i;



	/*

	 * we need to iterate on all fingers to decide if we have a press

	 * or a release event in our touchscreen emulation.

	 */

	for (i = 0; i < MAX_SLOTS; ++i) {

		struct mmm_finger *f = &md->f[i];

		if (!f->valid) {
@@ -183,34 +176,11 @@ static void mmm_filter_event(struct mmm_data *md, struct input_dev *input) 
						wide ? f->w : f->h);

			input_event(input, EV_ABS, ABS_MT_TOUCH_MINOR,

						wide ? f->h : f->w);

			/*

			 * touchscreen emulation: maintain the age rank

			 * of this finger, decide if we have a press

			 */

			if (f->rank == 0) {

				f->rank = ++(md->num);

				if (f->rank == 1)

					pressed = true;

			}

			if (f->rank == 1)

			/* touchscreen emulation: pick the oldest contact */

			if (!oldest || ((f->id - oldest->id) & (SHRT_MAX + 1)))

				oldest = f;

		} else {

			/* this finger took off the screen */

			/* touchscreen emulation: maintain age rank of others */

			int j;



			for (j = 0; j < 10; ++j) {

				struct mmm_finger *g = &md->f[j];

				if (g->rank > f->rank) {

					g->rank--;

					if (g->rank == 1)

						oldest = g;

				}

			}

			f->rank = 0;

			--(md->num);

			if (md->num == 0)

				released = true;

			input_event(input, EV_ABS, ABS_MT_TRACKING_ID, -1);

		}

		f->prev_touch = f->touch;
@@ -219,11 +189,10 @@ static void mmm_filter_event(struct mmm_data *md, struct input_dev *input) 


	/* touchscreen emulation */

	if (oldest) {

		if (pressed)

		input_event(input, EV_KEY, BTN_TOUCH, 1);

		input_event(input, EV_ABS, ABS_X, oldest->x);

		input_event(input, EV_ABS, ABS_Y, oldest->y);

	} else if (released) {

	} else {

		input_event(input, EV_KEY, BTN_TOUCH, 0);

	}

	input_sync(input);

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