[PATCH 3.16.y-ckt 175/180] Input: elantech - fix crc_enabled for Fujitsu H730

[Luis Henriques]

3.16.7-ckt11 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ulrik De Bie <ulrik.debie-os at e2big.org>

commit 0dc1587905a50f8f61bbc29e850aa592821e4bea upstream.

The Fujitsu H730 does not work with crc_enabled = 0, even though the
crc_enabled bit in the firmware version indicated it would. When switching
this value to crc_enabled to 1, the touchpad works. This patch uses DMI to
detect H730.

Reported-by: Stefan Valouch <stefan at valouch.com>
Tested-by: Stefan Valouch <stefan at valouch.com>
Tested-by: Alfredo Gemma <alfredo.gemma at gmail.com>
Signed-off-by: Ulrik De Bie <ulrik.debie-os at e2big.org>
Acked-by: Hans de Goede <hdegoede at redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov at gmail.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/input/mouse/elantech.c | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/drivers/input/mouse/elantech.c b/drivers/input/mouse/elantech.c
index 29365c60e514..687c149aa12d 100644
--- a/drivers/input/mouse/elantech.c
+++ b/drivers/input/mouse/elantech.c
@@ -1374,6 +1374,22 @@ static int elantech_reconnect(struct psmouse *psmouse)
 }
 
 /*
+ * Some hw_version 4 models do not work with crc_disabled
+ */
+static const struct dmi_system_id elantech_dmi_force_crc_enabled[] = {
+#if defined(CONFIG_DMI) && defined(CONFIG_X86)
+	{
+		/* Fujitsu H730 does not work with crc_enabled == 0 */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "CELSIUS H730"),
+		},
+	},
+#endif
+	{ }
+};
+
+/*
  * Some hw_version 3 models go into error state when we try to set
  * bit 3 and/or bit 1 of r10.
  */
@@ -1450,7 +1466,8 @@ static int elantech_set_properties(struct elantech_data *etd)
 	 * The signatures of v3 and v4 packets change depending on the
 	 * value of this hardware flag.
 	 */
-	etd->crc_enabled = ((etd->fw_version & 0x4000) == 0x4000);
+	etd->crc_enabled = (etd->fw_version & 0x4000) == 0x4000 ||
+			   dmi_check_system(elantech_dmi_force_crc_enabled);
 
 	/* Enable real hardware resolution on hw_version 3 ? */
 	etd->set_hw_resolution = !dmi_check_system(no_hw_res_dmi_table);