Input: alps - fix a mismatch between a condition check and its comment

commit 771a081e44a9baa1991ef011cc453ef425591740 upstream.

In the function alps_is_cs19_trackpoint(), we check if the param[1] is
in the 0x20~0x2f range, but the code we wrote for this checking is not
correct:
(param[1] & 0x20) does not mean param[1] is in the range of 0x20~0x2f,
it also means the param[1] is in the range of 0x30~0x3f, 0x60~0x6f...

Now fix it with a new condition checking ((param[1] & 0xf0) == 0x20).

Fixes: 7e4935ccc323 ("Input: alps - don't handle ALPS cs19 trackpoint-only device")
Cc: stable@vger.kernel.org
Signed-off-by: Hui Wang <hui.wang@canonical.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/input/mouse/alps.c b/drivers/input/mouse/alps.c
index 0bc1c6a7885228f9ebfc431a8371c6a2fee55125..21bb1ed97f9f2abb35f8ae8273ae7a0757d963e5 100644 (file)
--- a/drivers/input/mouse/alps.c
+++ b/drivers/input/mouse/alps.c
@@ -2875,7 +2875,7 @@ static bool alps_is_cs19_trackpoint(struct psmouse *psmouse)
         * trackpoint-only devices have their variant_ids equal
         * TP_VARIANT_ALPS and their firmware_ids are in 0x20~0x2f range.
         */
-       return param[0] == TP_VARIANT_ALPS && (param[1] & 0x20);
+       return param[0] == TP_VARIANT_ALPS && ((param[1] & 0xf0) == 0x20);
 }
 
 static int alps_identify(struct psmouse *psmouse, struct alps_data *priv)