input: mt: Identify pointer emulation contact

Commit Message

Henrik Rydberg Dec. 9, 2010, 11:19 p.m. UTC

None

Patch

diff --git a/drivers/input/input-mt.c b/drivers/input/input-mt.c
index afaf059..bcd2c22 100644
--- a/drivers/input/input-mt.c
+++ b/drivers/input/input-mt.c
@@ -105,7 +105,8 @@  EXPORT_SYMBOL(input_mt_report_slot_state);
  * @dev: input device with allocated MT slots
  *
  * Performs legacy pointer emulation via BTN_TOUCH, ABS_X, ABS_Y and
- * ABS_PRESSURE. Touchpad finger count is emulated using
+ * ABS_PRESSURE. If enabled, ABS_TRACKING_ID is emitted whenever the
+ * pointer contact changes. Touchpad finger count is emulated using
  * BTN_TOOL_FINGER, BTN_TOOL_DOUBLETAP, BTN_TOOL_TRIPLETAP and
  * BTN_TOOL_QUADTAP.
  *
@@ -146,6 +147,7 @@  void input_mt_report_pointer_emulation(struct input_dev *dev)
 		input_event(dev, EV_ABS, ABS_X, x);
 		input_event(dev, EV_ABS, ABS_Y, y);
 		input_event(dev, EV_ABS, ABS_PRESSURE, p);
+		input_event(dev, EV_ABS, ABS_TRACKING_ID, oldid);
 	} else {
 		input_event(dev, EV_ABS, ABS_PRESSURE, 0);
 	}
diff --git a/include/linux/input.h b/include/linux/input.h
index 65f7799..01dde9b 100644
--- a/include/linux/input.h
+++ b/include/linux/input.h
@@ -716,6 +716,7 @@  struct input_keymap_entry {
 #define ABS_TILT_X		0x1a
 #define ABS_TILT_Y		0x1b
 #define ABS_TOOL_WIDTH		0x1c
+#define ABS_TRACKING_ID		0x1d	/* ID of contact governing ABS_{X,Y} */
 
 #define ABS_VOLUME		0x20