[PATCH] [31/98] Input: elantech - discard the first 2 positions on some firmwares

[Andi Kleen <andi@firstfloor.org>]

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2.6.35-longterm review patch.  If anyone has any objections, please let me know.

------------------
From: Éric Piel <eric.piel@tremplin-utc.net>

commit 7f29f17b57255b6395046805a98bc663ded63fb8 upstream.

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>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
[bwh: Adjust for 2.6.32]
[ak: adjust for 2.6.35]
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
 drivers/input/mouse/elantech.c |   21 ++++++++++-----------
 drivers/input/mouse/elantech.h |    7 ++++---
 2 files changed, 14 insertions(+), 14 deletions(-)

Index: linux-2.6.35.y/drivers/input/mouse/elantech.c
===================================================================
--- linux-2.6.35.y.orig/drivers/input/mouse/elantech.c
+++ linux-2.6.35.y/drivers/input/mouse/elantech.c
@@ -185,7 +185,6 @@ static void elantech_report_absolute_v1(
 	struct elantech_data *etd = psmouse->private;
 	unsigned char *packet = psmouse->packet;
 	int fingers;
-	static int old_fingers;
 
 	if (etd->fw_version < 0x020000) {
 		/*
@@ -203,11 +202,14 @@ static void elantech_report_absolute_v1(
 	}
 
 	if (etd->jumpy_cursor) {
-		/* Discard packets that are likely to have bogus coordinates */
-		if (fingers > old_fingers) {
-			elantech_debug("discarding packet\n");
-			goto discard_packet_v1;
-		}
+		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("elantech.c: discarding packet\n");
+			return;
+ 		}
 	}
 
 	input_report_key(dev, BTN_TOUCH, fingers != 0);
@@ -238,9 +240,6 @@ static void elantech_report_absolute_v1(
 	}
 
 	input_sync(dev);
-
- discard_packet_v1:
-	old_fingers = fingers;
 }
 
 /*
@@ -733,13 +732,14 @@ int elantech_init(struct psmouse *psmous
 	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("elantech.c: firmware version 2.0.34/2.6.0 detected, "
+			"enabling jumpy cursor workaround\n");
+		etd->jumpy_cursor = true;
 	}
 
 	if (elantech_set_absolute_mode(psmouse)) {
Index: linux-2.6.35.y/drivers/input/mouse/elantech.h
===================================================================
--- linux-2.6.35.y.orig/drivers/input/mouse/elantech.h
+++ linux-2.6.35.y/drivers/input/mouse/elantech.h
@@ -100,10 +100,11 @@ struct elantech_data {
 	unsigned char reg_26;
 	unsigned char debug;
 	unsigned char capabilities;
-	unsigned char paritycheck;
-	unsigned char jumpy_cursor;
+	bool paritycheck;
+	bool jumpy_cursor;
 	unsigned char hw_version;
-	unsigned int  fw_version;
+	unsigned int fw_version;
+	unsigned int single_finger_reports;
 	unsigned char parity[256];
 };