[PATCH libinput] touchpad: always enable the bottom-most area for thumb detection

[Peter Hutterer]

If the touchpad is higher than 50mm, enable bottom area thumb detection. This
only applies to the bottom-most 8mm and only if the touch remains unmoving in
that area.

Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
---
 src/evdev-mt-touchpad.c | 36 ++++++++++++++++++++----------------
 1 file changed, 20 insertions(+), 16 deletions(-)

diff --git a/src/evdev-mt-touchpad.c b/src/evdev-mt-touchpad.c
index 64ec446..a683d9a 100644
--- a/src/evdev-mt-touchpad.c
+++ b/src/evdev-mt-touchpad.c
@@ -1765,13 +1765,6 @@ tp_init_thumb(struct tp_dispatch *tp)
 	if (!tp->buttons.is_clickpad)
 		return 0;
 
-	abs = libevdev_get_abs_info(device->evdev, ABS_MT_PRESSURE);
-	if (!abs)
-		return 0;
-
-	if (abs->maximum - abs->minimum < 255)
-		return 0;
-
 	/* if the touchpad is less than 50mm high, skip thumb detection.
 	 * it's too small to meaningfully interact with a thumb on the
 	 * touchpad */
@@ -1779,6 +1772,23 @@ tp_init_thumb(struct tp_dispatch *tp)
 	if (h < 50)
 		return 0;
 
+	tp->thumb.detect_thumbs = true;
+	tp->thumb.threshold = INT_MAX;
+
+	/* detect thumbs by pressure in the bottom 15mm, detect thumbs by
+	 * lingering in the bottom 8mm */
+	ymax = tp->device->abs.absinfo_y->maximum;
+	yres = tp->device->abs.absinfo_y->resolution;
+	tp->thumb.upper_thumb_line = ymax - yres * 15;
+	tp->thumb.lower_thumb_line = ymax - yres * 8;
+
+	abs = libevdev_get_abs_info(device->evdev, ABS_MT_PRESSURE);
+	if (!abs)
+		goto out;
+
+	if (abs->maximum - abs->minimum < 255)
+		goto out;
+
 	/* Our reference touchpad is the T440s with 42x42 resolution.
 	 * Higher-res touchpads exhibit higher pressure for the same
 	 * interaction. On the T440s, the threshold value is 100, you don't
@@ -1790,17 +1800,11 @@ tp_init_thumb(struct tp_dispatch *tp)
 	yres = tp->device->abs.absinfo_y->resolution;
 	threshold = 100.0 * hypot(xres, yres)/hypot(42, 42);
 	tp->thumb.threshold = max(100, threshold);
-	tp->thumb.detect_thumbs = true;
-
-	/* detect thumbs by pressure in the bottom 15mm, detect thumbs by
-	 * lingering in the bottom 8mm */
-	ymax = tp->device->abs.absinfo_y->maximum;
-	yres = tp->device->abs.absinfo_y->resolution;
-	tp->thumb.upper_thumb_line = ymax - yres * 15;
-	tp->thumb.lower_thumb_line = ymax - yres * 8;
 
+out:
 	log_debug(tp_libinput_context(tp),
-		  "thumb: enabled thumb detection on '%s'\n",
+		  "thumb: enabled thumb detection%s on '%s'\n",
+		  tp->thumb.threshold != INT_MAX ? " (+pressure)" : "",
 		  device->devname);
 
 	return 0;
-- 
2.4.3