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Commit 55746d28 authored by Hans de Goede's avatar Hans de Goede Committed by Jiri Kosina
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HID: multitouch: Only look at non touch fields in first packet of a frame 



Devices in "single finger hybrid mode" will send one report per finger,
on some devices only the first report of such a multi-packet frame will
contain a value for BTN_LEFT, in subsequent reports (if multiple fingers
are down) the value is always 0, causing hid-mt to report BTN_LEFT going
1 - 0 - 1 - 0 when pressing a clickpad and putting down a second finger.
This happens for example on USB 0603:0002 mt touchpads.

This commit fixes this by only reporting non touch fields for the first
packet of a (possibly) multi-packet frame.

Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
Reviewed-by: default avatarBenjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
parent af8dc4d0

drivers/hid/hid-multitouch.c

+15 −2
Original line number Diff line number Diff line
@@ -787,9 +787,11 @@ static int mt_touch_event(struct hid_device *hid, struct hid_field *field, 
}



static void mt_process_mt_event(struct hid_device *hid, struct hid_field *field,

				struct hid_usage *usage, __s32 value)

				struct hid_usage *usage, __s32 value,

				bool first_packet)

{

	struct mt_device *td = hid_get_drvdata(hid);

	__s32 cls = td->mtclass.name;

	__s32 quirks = td->mtclass.quirks;

	struct input_dev *input = field->hidinput->input;
@@ -846,6 +848,15 @@ static void mt_process_mt_event(struct hid_device *hid, struct hid_field *field, 
			break;



		default:

			/*

			 * For Win8 PTP touchpads we should only look at

			 * non finger/touch events in the first_packet of

			 * a (possible) multi-packet frame.

			 */

			if ((cls == MT_CLS_WIN_8 || cls == MT_CLS_WIN_8_DUAL) &&

			    !first_packet)

				return;



			if (usage->type)

				input_event(input, usage->type, usage->code,

						value);
@@ -866,6 +877,7 @@ static void mt_touch_report(struct hid_device *hid, struct hid_report *report) 
	struct mt_device *td = hid_get_drvdata(hid);

	__s32 cls = td->mtclass.name;

	struct hid_field *field;

	bool first_packet;

	unsigned count;

	int r, n, scantime = 0;
@@ -901,6 +913,7 @@ static void mt_touch_report(struct hid_device *hid, struct hid_report *report) 
	}

	td->prev_scantime = scantime;



	first_packet = td->num_received == 0;

	for (r = 0; r < report->maxfield; r++) {

		field = report->field[r];

		count = field->report_count;
@@ -910,7 +923,7 @@ static void mt_touch_report(struct hid_device *hid, struct hid_report *report) 


		for (n = 0; n < count; n++)

			mt_process_mt_event(hid, field, &field->usage[n],

					field->value[n]);

					    field->value[n], first_packet);

	}



	if (td->num_received >= td->num_expected)