[SRU][B/OEM-B/D/OEM-OSP1-B/E][PATCH v2 2/2] Input: alps - fix a mismatch between a condition check and its comment

Hui Wang hui.wang at canonical.com
Fri Jul 19 14:39:17 UTC 2019

BugLink: https://bugs.launchpad.net/bugs/1836752

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
(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 at vger.kernel.org
Signed-off-by: Hui Wang <hui.wang at canonical.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov at gmail.com>
(cherry picked from commit 771a081e44a9baa1991ef011cc453ef425591740
Signed-off-by: Hui Wang <hui.wang at canonical.com>
 drivers/input/mouse/alps.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/input/mouse/alps.c b/drivers/input/mouse/alps.c
index 11a4363c3b60..dd80ff6cc427 100644
--- a/drivers/input/mouse/alps.c
+++ b/drivers/input/mouse/alps.c
@@ -2879,7 +2879,7 @@ 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)

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