3 files changed, 69 insertions, 12 deletions

diff --git a/src/evdev-mt-touchpad.c b/src/evdev-mt-touchpad.c
index eb950a2..99963e6 100644
--- a/src/evdev-mt-touchpad.c
+++ b/src/evdev-mt-touchpad.c
@@ -2372,8 +2372,9 @@ tp_init_pressure(struct tp_dispatch *tp,
 		 struct evdev_device *device)
 {
 	const struct input_absinfo *abs;
-	unsigned int range;
 	unsigned int code = ABS_PRESSURE;
+	const char *prop;
+	int hi, lo;
 
 	if (tp->has_mt)
 		code = ABS_MT_PRESSURE;
@@ -2383,25 +2384,44 @@ tp_init_pressure(struct tp_dispatch *tp,
 		return;
 	}
 
-	tp->pressure.use_pressure = true;
-
 	abs = libevdev_get_abs_info(device->evdev, code);
 	assert(abs);
 
-	range = abs->maximum - abs->minimum;
+	prop = udev_device_get_property_value(device->udev_device,
+					      "LIBINPUT_ATTR_PRESSURE_RANGE");
+	if (prop) {
+		if (!parse_pressure_range_property(prop, &hi, &lo)) {
+			evdev_log_bug_client(device,
+				     "discarding invalid pressure range '%s'\n",
+				     prop);
+			return;
+		}
 
-	if (device->model_flags & EVDEV_MODEL_ELANTECH_TOUCHPAD) {
-		tp->pressure.high = 24;
-		tp->pressure.low = 10;
-	} else if (device->model_flags & EVDEV_MODEL_CYAPA) {
-		tp->pressure.high = 10;
-		tp->pressure.low = 8;
+		if (hi == 0 && lo == 0) {
+			evdev_log_info(device,
+			       "pressure-based touch detection disabled\n");
+			return;
+		}
 	} else {
+		unsigned int range = abs->maximum - abs->minimum;
+
 		/* Approximately the synaptics defaults */
-		tp->pressure.high = abs->minimum + 0.12 * range;
-		tp->pressure.low = abs->minimum + 0.10 * range;
+		hi = abs->minimum + 0.12 * range;
+		lo = abs->minimum + 0.10 * range;
+	}
+
+	if (hi > abs->maximum || hi < abs->minimum ||
+	    lo > abs->maximum || lo < abs->minimum) {
+		evdev_log_bug_libinput(device,
+			       "discarding out-of-bounds pressure range %d:%d\n",
+			       hi, lo);
+		return;
 	}
 
+	tp->pressure.use_pressure = true;
+	tp->pressure.high = hi;
+	tp->pressure.low = lo;
+
 	evdev_log_debug(device,
 			"using pressure-based touch detection\n");
 }
diff --git a/src/libinput-util.c b/src/libinput-util.c
index 351bbe4..38594fa 100644
--- a/src/libinput-util.c
+++ b/src/libinput-util.c
@@ -360,6 +360,42 @@ parse_tpkbcombo_layout_poperty(const char *prop,
 }
 
 /**
+ * Parses a string of the format "a:b" where both a and b must be integer
+ * numbers and a > b. Also allowed is the special string vaule "none" which
+ * amounts to unsetting the property.
+ *
+ * @param prop The value of the property
+ * @param hi Set to the first digit or 0 in case of 'none'
+ * @param lo Set to the second digit or 0 in case of 'none'
+ * @return true on success, false otherwise
+ */
+bool
+parse_pressure_range_property(const char *prop, int *hi, int *lo)
+{
+	int first, second;
+
+	if (!prop)
+		return false;
+
+	if (streq(prop, "none")) {
+		*hi = 0;
+		*lo = 0;
+		return true;
+	}
+
+	if (sscanf(prop, "%d:%d", &first, &second) != 2)
+		return false;
+
+	if (second >= first)
+		return false;
+
+	*hi = first;
+	*lo = second;
+
+	return true;
+}
+
+/**
  * Return the next word in a string pointed to by state before the first
  * separator character. Call repeatedly to tokenize a whole string.
  *
diff --git a/src/libinput-util.h b/src/libinput-util.h
index 3fe0a02..4e97e01 100644
--- a/src/libinput-util.h
+++ b/src/libinput-util.h
@@ -393,6 +393,7 @@ int parse_mouse_wheel_click_count_property(const char *prop);
 double parse_trackpoint_accel_property(const char *prop);
 bool parse_dimension_property(const char *prop, size_t *width, size_t *height);
 bool parse_calibration_property(const char *prop, float calibration[6]);
+bool parse_pressure_range_property(const char *prop, int *hi, int *lo);
 
 enum tpkbcombo_layout {
 	TPKBCOMBO_LAYOUT_UNKNOWN,