[PATCH v2] Input: ALPS - Fix ALPS touchpad detection

[Akio Idehara <zbe64533@gmail.com>]

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>
---
  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 f274c28..2f95308 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 bd87380..4c6a72d 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;

  	/*
-- 
1.7.9