From 99c90ab31fad855b9da9dee3a5aa6c27f263e9d6 Mon Sep 17 00:00:00 2001
From: Akio Idehara <zbe64533@gmail.com>
Date: Fri, 24 Feb 2012 00:33:22 -0800
Subject: [PATCH] Input: ALPS - fix touchpad detection when buttons are pressed

ALPS touchpad detection fails if some buttons of ALPS are pressed.
The reason is that the "E6" query response byte is different from
what is expected.

This was tested on a Toshiba Portege R500.

Cc: stable <stable@vger.kernel.org>
Signed-off-by: Akio Idehara <zbe64533@gmail.com>
Tested-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
---
 Documentation/input/alps.txt | 3 ++-
 drivers/input/mouse/alps.c   | 7 +++++--
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/Documentation/input/alps.txt b/Documentation/input/alps.txt
index f274c28b51035..2f95308251d41 100644
--- a/Documentation/input/alps.txt
+++ b/Documentation/input/alps.txt
@@ -13,7 +13,8 @@ Detection
 
 All ALPS touchpads should respond to the "E6 report" command sequence:
 E8-E6-E6-E6-E9. An ALPS touchpad should respond with either 00-00-0A or
-00-00-64.
+00-00-64 if no buttons are pressed. The bits 0-2 of the first byte will be 1s
+if some buttons are pressed.
 
 If the E6 report is successful, the touchpad model is identified using the "E7
 report" sequence: E8-E7-E7-E7-E9. The response is the model signature and is
diff --git a/drivers/input/mouse/alps.c b/drivers/input/mouse/alps.c
index bd87380bd879e..4c6a72d3d48c3 100644
--- a/drivers/input/mouse/alps.c
+++ b/drivers/input/mouse/alps.c
@@ -952,7 +952,9 @@ static const struct alps_model_info *alps_get_model(struct psmouse *psmouse, int
 
 	/*
 	 * First try "E6 report".
-	 * ALPS should return 0,0,10 or 0,0,100
+	 * ALPS should return 0,0,10 or 0,0,100 if no buttons are pressed.
+	 * The bits 0-2 of the first byte will be 1s if some buttons are
+	 * pressed.
 	 */
 	param[0] = 0;
 	if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES) ||
@@ -968,7 +970,8 @@ static const struct alps_model_info *alps_get_model(struct psmouse *psmouse, int
 	psmouse_dbg(psmouse, "E6 report: %2.2x %2.2x %2.2x",
 		    param[0], param[1], param[2]);
 
-	if (param[0] != 0 || param[1] != 0 || (param[2] != 10 && param[2] != 100))
+	if ((param[0] & 0xf8) != 0 || param[1] != 0 ||
+	    (param[2] != 10 && param[2] != 100))
 		return NULL;
 
 	/*
-- 
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