[PATCH libinput] touchpad: allow BTN_LEFT in clickfinger mode without touches

[Peter Hutterer]

On the Logitech T650 it's quite easy to trigger a click without touching the
surface. For software buttons we discard those clicks because we can't tell
where the finger is to decide on left vs right click.

It takes effort to trigger a click with two fingers without triggering a touch
though, so in clickfinger mode post a click without toucheas as single-finger
click.

https://bugs.freedesktop.org/show_bug.cgi?id=90150

Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
---
 src/evdev-mt-touchpad-buttons.c |  6 ++++--
 test/touchpad.c                 | 30 ++++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/src/evdev-mt-touchpad-buttons.c b/src/evdev-mt-touchpad-buttons.c
index c907ecc..7f60a53 100644
--- a/src/evdev-mt-touchpad-buttons.c
+++ b/src/evdev-mt-touchpad-buttons.c
@@ -804,6 +804,7 @@ tp_notify_clickpadbutton(struct tp_dispatch *tp,
 	if (tp->buttons.click_method == LIBINPUT_CONFIG_CLICK_METHOD_CLICKFINGER &&
 	    state == LIBINPUT_BUTTON_STATE_PRESSED) {
 		switch (tp->nfingers_down) {
+		case 0:
 		case 1: button = BTN_LEFT; break;
 		case 2: button = BTN_RIGHT; break;
 		case 3: button = BTN_MIDDLE; break;
@@ -865,7 +866,8 @@ tp_post_clickpadbutton_buttons(struct tp_dispatch *tp, uint64_t time)
 			}
 		}
 
-		if (area == 0) {
+		if (area == 0 &&
+		    tp->buttons.click_method != LIBINPUT_CONFIG_CLICK_METHOD_CLICKFINGER) {
 			/* No touches, wait for a touch before processing */
 			tp->buttons.click_pending = true;
 			return 0;
@@ -877,7 +879,7 @@ tp_post_clickpadbutton_buttons(struct tp_dispatch *tp, uint64_t time)
 			button = evdev_to_left_handed(tp->device, BTN_RIGHT);
 		else if (area & LEFT)
 			button = evdev_to_left_handed(tp->device, BTN_LEFT);
-		else /* main area is always BTN_LEFT */
+		else /* main or no area (for clickfinger) is always BTN_LEFT */
 			button = BTN_LEFT;
 
 		tp->buttons.active = button;
diff --git a/test/touchpad.c b/test/touchpad.c
index c04ef11..db981dc 100644
--- a/test/touchpad.c
+++ b/test/touchpad.c
@@ -1506,6 +1506,32 @@ START_TEST(touchpad_1fg_clickfinger)
 }
 END_TEST
 
+START_TEST(touchpad_1fg_clickfinger_no_touch)
+{
+	struct litest_device *dev = litest_current_device();
+	struct libinput *li = dev->libinput;
+	enum libinput_config_status status;
+
+	status = libinput_device_config_click_set_method(dev->libinput_device,
+							 LIBINPUT_CONFIG_CLICK_METHOD_CLICKFINGER);
+	ck_assert_int_eq(status, LIBINPUT_CONFIG_STATUS_SUCCESS);
+
+	litest_drain_events(li);
+
+	litest_event(dev, EV_KEY, BTN_LEFT, 1);
+	litest_event(dev, EV_SYN, SYN_REPORT, 0);
+	litest_event(dev, EV_KEY, BTN_LEFT, 0);
+	litest_event(dev, EV_SYN, SYN_REPORT, 0);
+
+	libinput_dispatch(li);
+
+	litest_assert_button_event(li, BTN_LEFT,
+				   LIBINPUT_BUTTON_STATE_PRESSED);
+	litest_assert_button_event(li, BTN_LEFT,
+				   LIBINPUT_BUTTON_STATE_RELEASED);
+}
+END_TEST
+
 START_TEST(touchpad_2fg_clickfinger)
 {
 	struct litest_device *dev = litest_current_device();
@@ -1785,6 +1811,9 @@ START_TEST(clickpad_btn_left)
 	struct litest_device *dev = litest_current_device();
 	struct libinput *li = dev->libinput;
 
+	libinput_device_config_click_set_method(dev->libinput_device,
+						LIBINPUT_CONFIG_CLICK_METHOD_BUTTON_AREAS);
+
 	litest_drain_events(li);
 
 	/* A clickpad always needs a finger down to tell where the
@@ -4119,6 +4148,7 @@ int main(int argc, char **argv) {
 	litest_add("touchpad:tap", clickpad_2fg_tap_click, LITEST_CLICKPAD, LITEST_SINGLE_TOUCH|LITEST_APPLE_CLICKPAD);
 
 	litest_add("touchpad:clickfinger", touchpad_1fg_clickfinger, LITEST_CLICKPAD, LITEST_ANY);
+	litest_add("touchpad:clickfinger", touchpad_1fg_clickfinger_no_touch, LITEST_CLICKPAD, LITEST_ANY);
 	litest_add("touchpad:clickfinger", touchpad_2fg_clickfinger, LITEST_CLICKPAD, LITEST_ANY);
 	litest_add("touchpad:clickfinger", touchpad_clickfinger_to_area_method, LITEST_CLICKPAD, LITEST_ANY);
 	litest_add("touchpad:clickfinger",
-- 
2.3.5