Input: alps - only Dell laptops have separate button bits for v2 dualpoint sticks

It turns out that only Dell laptops have the separate button bits for
v2 dualpoint sticks and that commit 92bac83dd79e ("Input: alps - non
interleaved V2 dualpoint has separate stick button bits") causes
regressions on Toshiba laptops.

This commit adds a check for Dell laptops to the code for handling these
extra button bits, fixing this regression.

This patch has been tested on a Dell Latitude D620 to make sure that it
does not reintroduce the original problem.

Reported-and-tested-by: Douglas Christman <douglaschristman@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/drivers/input/mouse/alps.c b/drivers/input/mouse/alps.c
index 113d6f1516a5..4d246861d692 100644
--- a/drivers/input/mouse/alps.c
+++ b/drivers/input/mouse/alps.c
@@ -20,6 +20,7 @@
 #include <linux/input/mt.h>
 #include <linux/serio.h>
 #include <linux/libps2.h>
+#include <linux/dmi.h>
 
 #include "psmouse.h"
 #include "alps.h"
@@ -99,6 +100,7 @@ static const struct alps_nibble_commands alps_v6_nibble_commands[] = {
 #define ALPS_FOUR_BUTTONS       0x40    /* 4 direction button present */
 #define ALPS_PS2_INTERLEAVED    0x80    /* 3-byte PS/2 packet interleaved with
                                            6-byte ALPS packet */
+#define ALPS_DELL               0x100   /* device is a Dell laptop */
 #define ALPS_BUTTONPAD          0x200   /* device is a clickpad */
 
 static const struct alps_model_info alps_model_data[] = {
@@ -251,9 +253,9 @@ static void alps_process_packet_v1_v2(struct psmouse *psmouse)
                 return;
         }
 
-        /* Non interleaved V2 dualpoint has separate stick button bits */
+        /* Dell non interleaved V2 dualpoint has separate stick button bits */
         if (priv->proto_version == ALPS_PROTO_V2 &&
-            priv->flags == (ALPS_PASS | ALPS_DUALPOINT)) {
+            priv->flags == (ALPS_DELL | ALPS_PASS | ALPS_DUALPOINT)) {
                 left |= packet[0] & 1;
                 right |= packet[0] & 2;
                 middle |= packet[0] & 4;
@@ -2550,6 +2552,8 @@ static int alps_set_protocol(struct psmouse *psmouse,
         priv->byte0 = protocol->byte0;
         priv->mask0 = protocol->mask0;
         priv->flags = protocol->flags;
+        if (dmi_name_in_vendors("Dell"))
+                priv->flags |= ALPS_DELL;
 
         priv->x_max = 2000;
         priv->y_max = 1400;