Input: synaptics - relax capability ID checks on newer hardware

Older firmwares fixed the middle byte of the Synaptics capabilities
query to 0x47, but starting with firmware 7.5 the middle byte
represents submodel ID, sometimes also called "dash number".
Reported-and-tested-by: Miroslav Šulc <fordfrog@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

drivers/input/mouse/synaptics.c

@@ -141,8 +141,13 @@ static int synaptics_capability(struct psmouse *psmouse)
 	priv->capabilities = (cap[0] << 16) | (cap[1] << 8) | cap[2];
 	priv->ext_cap = priv->ext_cap_0c = 0;
 
-	if (!SYN_CAP_VALID(priv->capabilities))
+	/*
+	 * Older firmwares had submodel ID fixed to 0x47
+	 */
+	if (SYN_ID_FULL(priv->identity) < 0x705 &&
+	    SYN_CAP_SUBMODEL_ID(priv->capabilities) != 0x47) {
 		return -1;
+	}
 
 	/*
 	 * Unless capExtended is set the rest of the flags should be ignored

drivers/input/mouse/synaptics.h

@@ -47,7 +47,7 @@
 #define SYN_CAP_FOUR_BUTTON(c)		((c) & (1 << 3))
 #define SYN_CAP_MULTIFINGER(c)		((c) & (1 << 1))
 #define SYN_CAP_PALMDETECT(c)		((c) & (1 << 0))
-#define SYN_CAP_VALID(c)		((((c) & 0x00ff00) >> 8) == 0x47)
+#define SYN_CAP_SUBMODEL_ID(c)		(((c) & 0x00ff00) >> 8)
 #define SYN_EXT_CAP_REQUESTS(c)		(((c) & 0x700000) >> 20)
 #define SYN_CAP_MULTI_BUTTON_NO(ec)	(((ec) & 0x00f000) >> 12)
 #define SYN_CAP_PRODUCT_ID(ec)		(((ec) & 0xff0000) >> 16)
@@ -66,6 +66,7 @@
 #define SYN_ID_MODEL(i)			(((i) >> 4) & 0x0f)
 #define SYN_ID_MAJOR(i)			((i) & 0x0f)
 #define SYN_ID_MINOR(i)			(((i) >> 16) & 0xff)
+#define SYN_ID_FULL(i)			((SYN_ID_MAJOR(i) << 8) | SYN_ID_MINOR(i))
 #define SYN_ID_IS_SYNAPTICS(i)		((((i) >> 8) & 0xff) == 0x47)
 
 /* synaptics special commands */