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

PATCH Applied Hui Wang 2 participants 2 messages Jul 19, 2019

Subsystems (4)
Stable branch HID Input drivers Alps ps/2 touchpad driver
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Hui Wang

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#0 lore raw

PATCH 1/1 Input: alps - Fix a mismatch between a condition check and its comment

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 [email protected]
Signed-off-by Hui Wang <[email protected]>
---
 drivers/input/mouse/alps.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/input/mouse/alps.c +1 -1
index 62ffea00902a..34700eda0429 100644
@@ -2876,7 +2876,7 @@ 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)
Signature · 1 line
2.17.1
maintainer Applied
#1 lore raw
Quoted 11 lines · Hui Wang

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 [email protected]
Signed-off-by Hui Wang <[email protected]>

Applied, thank you.

Quoted 20 lines
---
 drivers/input/mouse/alps.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/input/mouse/alps.c +1 -1
index 62ffea00902a..34700eda0429 100644
@@ -2876,7 +2876,7 @@ 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)
Signature · 1 line
2.17.1
Signature · 1 line
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