1 files changed, 86 insertions, 20 deletions

diff --git a/drivers/input/mouse/hgpk.c b/drivers/input/mouse/hgpk.c
index 222594742c39..b54f074ec307 100644
--- a/drivers/input/mouse/hgpk.c
+++ b/drivers/input/mouse/hgpk.c
@@ -40,6 +40,8 @@
 #include "psmouse.h"
 #include "hgpk.h"
 
+#define ILLEGAL_XY 999999
+
 static bool tpdebug;
 module_param(tpdebug, bool, 0644);
 MODULE_PARM_DESC(tpdebug, "enable debugging, dumping packets to KERN_DEBUG.");
@@ -47,9 +49,10 @@ MODULE_PARM_DESC(tpdebug, "enable debugging, dumping packets to KERN_DEBUG.");
 static int recalib_delta = 100;
 module_param(recalib_delta, int, 0644);
 MODULE_PARM_DESC(recalib_delta,
-	"packets containing a delta this large will cause a recalibration.");
+	"packets containing a delta this large will be discarded, and a "
+	"recalibration may be scheduled.");
 
-static int jumpy_delay = 1000;
+static int jumpy_delay = 20;
 module_param(jumpy_delay, int, 0644);
 MODULE_PARM_DESC(jumpy_delay,
 	"delay (ms) before recal after jumpiness detected");
@@ -96,25 +99,76 @@ static int hgpk_mode_from_name(const char *buf, int len)
 }
 
 /*
- * When the touchpad gets ultra-sensitive, one can keep their finger 1/2"
- * above the pad and still have it send packets.  This causes a jump cursor
- * when one places their finger on the pad.  We can probably detect the
- * jump as we see a large deltas (>= 100px).  In mouse mode, I've been
- * unable to even come close to 100px deltas during normal usage, so I think
- * this threshold is safe.  If a large delta occurs, trigger a recalibration.
+ * see if new value is within 20% of half of old value
+ */
+static int approx_half(int curr, int prev)
+{
+	int belowhalf, abovehalf;
+
+	if (curr < 5 || prev < 5)
+		return 0;
+
+	belowhalf = (prev * 8) / 20;
+	abovehalf = (prev * 12) / 20;
+
+	return belowhalf < curr && curr <= abovehalf;
+}
+
+/*
+ * Throw out oddly large delta packets, and any that immediately follow whose
+ * values are each approximately half of the previous.  It seems that the ALPS
+ * firmware emits errant packets, and they get averaged out slowly.
  */
-static void hgpk_jumpy_hack(struct psmouse *psmouse, int x, int y)
+static int hgpk_discard_decay_hack(struct psmouse *psmouse, int x, int y)
 {
 	struct hgpk_data *priv = psmouse->private;
+	int avx, avy;
+	bool do_recal = false;
+
+	avx = abs(x);
+	avy = abs(y);
+
+	/* discard if too big, or half that but > 4 times the prev delta */
+	if (avx > recalib_delta ||
+		(avx > recalib_delta / 2 && ((avx / 4) > priv->xlast))) {
+		hgpk_err(psmouse, "detected %dpx jump in x\n", x);
+		priv->xbigj = avx;
+	} else if (approx_half(avx, priv->xbigj)) {
+		hgpk_err(psmouse, "detected secondary %dpx jump in x\n", x);
+		priv->xbigj = avx;
+		priv->xsaw_secondary++;
+	} else {
+		if (priv->xbigj && priv->xsaw_secondary > 1)
+			do_recal = true;
+		priv->xbigj = 0;
+		priv->xsaw_secondary = 0;
+	}
 
-	if (abs(x) > recalib_delta || abs(y) > recalib_delta) {
-		hgpk_err(psmouse, ">%dpx jump detected (%d,%d)\n",
-				recalib_delta, x, y);
-		/* My car gets forty rods to the hogshead and that's the
-		 * way I likes it! */
+	if (avy > recalib_delta ||
+		(avy > recalib_delta / 2 && ((avy / 4) > priv->ylast))) {
+		hgpk_err(psmouse, "detected %dpx jump in y\n", y);
+		priv->ybigj = avy;
+	} else if (approx_half(avy, priv->ybigj)) {
+		hgpk_err(psmouse, "detected secondary %dpx jump in y\n", y);
+		priv->ybigj = avy;
+		priv->ysaw_secondary++;
+	} else {
+		if (priv->ybigj && priv->ysaw_secondary > 1)
+			do_recal = true;
+		priv->ybigj = 0;
+		priv->ysaw_secondary = 0;
+	}
+
+	priv->xlast = avx;
+	priv->ylast = avy;
+
+	if (do_recal && jumpy_delay) {
+		hgpk_err(psmouse, "scheduling recalibration\n");
 		psmouse_queue_work(psmouse, &priv->recalib_wq,
 				msecs_to_jiffies(jumpy_delay));
 	}
+
+	return priv->xbigj || priv->ybigj;
 }
 
 static void hgpk_reset_spew_detection(struct hgpk_data *priv)
@@ -131,6 +185,9 @@ static void hgpk_reset_hack_state(struct psmouse *psmouse)
 	struct hgpk_data *priv = psmouse->private;
 
 	priv->abs_x = priv->abs_y = -1;
+	priv->xlast = priv->ylast = ILLEGAL_XY;
+	priv->xbigj = priv->ybigj = 0;
+	priv->xsaw_secondary = priv->ysaw_secondary = 0;
 	hgpk_reset_spew_detection(priv);
 }
 
@@ -322,7 +379,7 @@ static void hgpk_process_advanced_packet(struct psmouse *psmouse)
 	 * tracking so that we don't erroneously detect a jump on next press.
 	 */
 	if (!down) {
-		hgpk_reset_hack_state(priv);
+		hgpk_reset_hack_state(psmouse);
 		goto done;
 	}
 
@@ -346,10 +403,14 @@ static void hgpk_process_advanced_packet(struct psmouse *psmouse)
 
 	/* Don't apply hacks in PT mode, it seems reliable */
 	if (priv->mode != HGPK_MODE_PENTABLET && priv->abs_x != -1) {
-		hgpk_jumpy_hack(psmouse,
-				priv->abs_x - x, priv->abs_y - y);
-		hgpk_spewing_hack(psmouse, left, right,
-				  priv->abs_x - x, priv->abs_y - y);
+		int x_diff = priv->abs_x - x;
+		int y_diff = priv->abs_y - y;
+		if (hgpk_discard_decay_hack(psmouse, x_diff, y_diff)) {
+			if (tpdebug)
+				hgpk_dbg(psmouse, "discarding\n");
+			goto done;
+		}
+		hgpk_spewing_hack(psmouse, left, right, x_diff, y_diff);
 	}
 
 	input_report_abs(idev, ABS_X, x);
@@ -370,7 +431,12 @@ static void hgpk_process_simple_packet(struct psmouse *psmouse)
 	int x = packet[1] - ((packet[0] << 4) & 0x100);
 	int y = ((packet[0] << 3) & 0x100) - packet[2];
 
-	hgpk_jumpy_hack(psmouse, x, y);
+	if (hgpk_discard_decay_hack(psmouse, x, y)) {
+		if (tpdebug)
+			hgpk_dbg(psmouse, "discarding\n");
+		return;
+	}
+
 	hgpk_spewing_hack(psmouse, left, right, x, y);
 
 	if (tpdebug)