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fw/services/touch: release an active touch when the last subscriber leaves #1892

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fw/services/touch: release an active touch when the last subscriber leaves #1892

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13 changes: 8 additions & 5 deletions src/fw/services/touch/touch.c
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Original file line number Diff line number Diff line change
Expand Up @@ -63,19 +63,22 @@ static void prv_add_subscriber_cb(PebbleTask task) {
static void prv_remove_subscriber_cb(PebbleTask task) {
mutex_lock(s_touch_mutex);
PBL_ASSERTN(s_subscriber_count > 0);
if (--s_subscriber_count == 0 && s_globally_enabled) {
const bool was_last_subscriber = (--s_subscriber_count == 0);
if (was_last_subscriber && s_globally_enabled) {
touch_sensor_set_enabled(false);
}
// An app whose shared touch subscription disappears (task exit, or both
// slots emptied) cannot have a live raw handler or nav dispatcher anymore;
// drop its raw-slot mark and the app-nav-active flag so a crashed app cannot
// leak backlight-follow behavior.
// An app whose shared touch subscription disappears (task exit, or both slots emptied) cannot have a live raw handler or nav dispatcher anymore; drop its raw-slot mark and the app-nav-active flag so a crashed app cannot leak backlight-follow behavior.
if (task == PebbleTask_App) {
s_raw_subscriber_tasks &= (uint8_t)~(1u << task);
s_app_nav_active = false;
}
PBL_LOG_DBG("Touch: subscriber removed, count=%" PRIu8, s_subscriber_count);
mutex_unlock(s_touch_mutex);

if (was_last_subscriber) {
// A finger down when the last subscriber goes away never gets a Liftoff otherwise (the sensor stops reporting), so the backlight hold counter stays pinned. Same teardown the global toggle performs.
touch_release_active();
}
}

void touch_init(void) {
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20 changes: 20 additions & 0 deletions tests/fw/services/test_touch.c
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Original file line number Diff line number Diff line change
Expand Up @@ -591,6 +591,26 @@ void test_touch__reset_mid_gesture_refuses_continuation(void) {
touch_handle_injected_update(TouchInjectPhase_End, 50, 60);
}

void test_touch__last_unsubscribe_with_finger_down_emits_liftoff(void) {
// Finger down, then the last subscriber goes away: the sensor powers down mid-gesture, so a Liftoff must be synthesized with the last coordinates (not zeros) or the backlight hold taken by the Touchdown never unwinds — the same teardown the global toggle performs.
s_add_subscriber_cb(PebbleTask_App);
touch_handle_update(TouchState_FingerDown, 30, 40);
fake_event_reset_count();

s_remove_subscriber_cb(PebbleTask_App);
cl_assert_equal_i(fake_event_get_count(), 1);
prv_assert_touch_event(TouchEvent_Liftoff, 30, 40);
}

void test_touch__last_unsubscribe_without_finger_no_liftoff(void) {
// No finger down: the last subscriber leaving must not fabricate a Liftoff.
s_add_subscriber_cb(PebbleTask_App);
fake_event_reset_count();

s_remove_subscriber_cb(PebbleTask_App);
cl_assert_equal_i(fake_event_get_count(), 0);
}

void test_touch__event_abi_unchanged(void) {
// non_navigational rides in the padding after type:8; x/y offsets and the
// overall size must not move, keeping the SDK struct app-compatible.
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