Input: elantech - discard the first 2 positions on some firmwares

According to the Dell/Ubuntu driver, what was previously observed as
"jumpy cursor" corresponds to the hardware sending incorrect data for
the first two reports of a one touch finger. So let's use the same
workaround as in the other driver. Also, detect another firmware
version with the same behaviour, as in the other driver.

Signed-off-by: Éric Piel <eric.piel@tremplin-utc.net>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 10 insertions, 11 deletions

diff --git a/drivers/input/mouse/elantech.c b/drivers/input/mouse/elantech.c
index b18862b2a70e..bd5b91da169e 100644
--- a/drivers/input/mouse/elantech.c
+++ b/drivers/input/mouse/elantech.c
@@ -185,7 +185,6 @@ static void elantech_report_absolute_v1(struct psmouse *psmouse)
         struct elantech_data *etd = psmouse->private;
         unsigned char *packet = psmouse->packet;
         int fingers;
-        static int old_fingers;
 
         if (etd->fw_version < 0x020000) {
                 /*
@@ -203,10 +202,13 @@ static void elantech_report_absolute_v1(struct psmouse *psmouse)
         }
 
         if (etd->jumpy_cursor) {
-                /* Discard packets that are likely to have bogus coordinates */
-                if (fingers > old_fingers) {
+                if (fingers != 1) {
+                        etd->single_finger_reports = 0;
+                } else if (etd->single_finger_reports < 2) {
+                        /* Discard first 2 reports of one finger, bogus */
+                        etd->single_finger_reports++;
                         elantech_debug("discarding packet\n");
-                        goto discard_packet_v1;
+                        return;
                 }
         }
 
@@ -238,9 +240,6 @@ static void elantech_report_absolute_v1(struct psmouse *psmouse)
         }
 
         input_sync(dev);
-
- discard_packet_v1:
-        old_fingers = fingers;
 }
 
 /*
@@ -733,13 +732,13 @@ int elantech_init(struct psmouse *psmouse)
         etd->capabilities = param[0];
 
         /*
-         * This firmware seems to suffer from misreporting coordinates when
+         * This firmware suffers from misreporting coordinates when
          * a touch action starts causing the mouse cursor or scrolled page
          * to jump. Enable a workaround.
          */
-        if (etd->fw_version == 0x020022) {
-                pr_info("firmware version 2.0.34 detected, enabling jumpy cursor workaround\n");
-                etd->jumpy_cursor = 1;
+        if (etd->fw_version == 0x020022 || etd->fw_version == 0x020600) {
+                pr_info("firmware version 2.0.34/2.6.0 detected, enabling jumpy cursor workaround\n");
+                etd->jumpy_cursor = true;
         }
 
         if (elantech_set_absolute_mode(psmouse)) {