2 files changed, 88 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)
diff --git a/drivers/input/mouse/hgpk.h b/drivers/input/mouse/hgpk.h
index bccdb26dca49..311c0e87fcbf 100644
--- a/drivers/input/mouse/hgpk.h
+++ b/drivers/input/mouse/hgpk.h
@@ -42,6 +42,8 @@ struct hgpk_data {
         struct delayed_work recalib_wq;
         int abs_x, abs_y;
         int dupe_count;
+        int xbigj, ybigj, xlast, ylast; /* jumpiness detection */
+        int xsaw_secondary, ysaw_secondary; /* jumpiness detection */
 };
 
 #define hgpk_dbg(psmouse, format, arg...)               \