Input: synaptics - gate forcepad support by DMI check

commit aa972409 upstream.

Unfortunately, ForcePad capability is not actually exported over PS/2, so
we have to resort to DMI checks.
Reported-by: Nicole Faerber <nicole.faerber@kernelconcepts.de>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

drivers/input/mouse/synaptics.c

@@ -615,6 +615,8 @@ static void synaptics_parse_agm(const unsigned char buf[],
 	priv->agm_pending = true;
 }
 
+static bool is_forcepad;
+
 static int synaptics_parse_hw_state(const unsigned char buf[],
 				    struct synaptics_data *priv,
 				    struct synaptics_hw_state *hw)
@@ -644,7 +646,7 @@ static int synaptics_parse_hw_state(const unsigned char buf[],
 		hw->left  = (buf[0] & 0x01) ? 1 : 0;
 		hw->right = (buf[0] & 0x02) ? 1 : 0;
 
-		if (SYN_CAP_FORCEPAD(priv->ext_cap_0c)) {
+		if (is_forcepad) {
 			/*
 			 * ForcePads, like Clickpads, use middle button
 			 * bits to report primary button clicks.
@@ -1613,10 +1615,28 @@ static const struct dmi_system_id olpc_dmi_table[] __initconst = {
 	{ }
 };
 
+static const struct dmi_system_id forcepad_dmi_table[] __initconst = {
+#if defined(CONFIG_DMI) && defined(CONFIG_X86)
+	{
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "HP EliteBook Folio 1040 G1"),
+		},
+	},
+#endif
+	{ }
+};
+
 void __init synaptics_module_init(void)
 {
 	impaired_toshiba_kbc = dmi_check_system(toshiba_dmi_table);
 	broken_olpc_ec = dmi_check_system(olpc_dmi_table);
+
+	/*
+	 * Unfortunately ForcePad capability is not exported over PS/2,
+	 * so we have to resort to checking DMI.
+	 */
+	is_forcepad = dmi_check_system(forcepad_dmi_table);
 }
 
 static int __synaptics_init(struct psmouse *psmouse, bool absolute_mode)

drivers/input/mouse/synaptics.h

@@ -77,12 +77,9 @@
  *					for noise.
  * 2	0x08	image sensor		image sensor tracks 5 fingers, but only
  *					reports 2.
+ * 2	0x01	uniform clickpad	whole clickpad moves instead of being
+ *					hinged at the top.
  * 2	0x20	report min		query 0x0f gives min coord reported
- * 2	0x80	forcepad		forcepad is a variant of clickpad that
- *					does not have physical buttons but rather
- *					uses pressure above certain threshold to
- *					report primary clicks. Forcepads also have
- *					clickpad bit set.
  */
 #define SYN_CAP_CLICKPAD(ex0c)		((ex0c) & 0x100000) /* 1-button ClickPad */
 #define SYN_CAP_CLICKPAD2BTN(ex0c)	((ex0c) & 0x000100) /* 2-button ClickPad */
@@ -91,7 +88,6 @@
 #define SYN_CAP_ADV_GESTURE(ex0c)	((ex0c) & 0x080000)
 #define SYN_CAP_REDUCED_FILTERING(ex0c)	((ex0c) & 0x000400)
 #define SYN_CAP_IMAGE_SENSOR(ex0c)	((ex0c) & 0x000800)
-#define SYN_CAP_FORCEPAD(ex0c)		((ex0c) & 0x008000)
 
 /* synaptics modes query bits */
 #define SYN_MODE_ABSOLUTE(m)		((m) & (1 << 7))