[PATCH 3.12 092/146] Input: elantech - fix touchpad initialization on Gigabyte U2442

Jiri Slaby
2014-06-09T09:02:30Z

From: Hans de Goede <hdegoede@redhat.com>

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

===============

commit 36189cc3cd57ab0f1cd75241f93fe01de928ac06 upstream.

The hw_version 3 Elantech touchpad on the Gigabyte U2442 does not accept
0x0b as initialization value for r10, this stand-alone version of the
driver: http://planet76.com/drivers/elantech/psmouse-elantech-v6.tar.bz2

Uses 0x03 which does work, so this means not setting bit 3 of r10 which
sets: "Enable Real H/W Resolution In Absolute mode"

Which will result in half the x and y resolution we get with that bit set,
so simply not setting it everywhere is not a solution. We've been unable to
find a way to identify touchpads where setting the bit will fail, so this
patch uses a dmi based blacklist for this.

https://bugzilla.kernel.org/show_bug.cgi?id=61151

Reported-by: Philipp Wolfer <ph.wolfer@gmail.com>
Tested-by: Philipp Wolfer <ph.wolfer@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
Documentation/input/elantech.txt | 5 ++++-
drivers/input/mouse/elantech.c | 26 +++++++++++++++++++++++++-
drivers/input/mouse/elantech.h | 1 +
3 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/Documentation/input/elantech.txt b/Documentation/input/elantech.txt
index 5602eb71ad5d..e1ae127ed099 100644
--- a/Documentation/input/elantech.txt
+++ b/Documentation/input/elantech.txt
@@ -504,9 +504,12 @@ byte 5:
* reg_10

bit 7 6 5 4 3 2 1 0
- 0 0 0 0 0 0 0 A
+ 0 0 0 0 R F T A

A: 1 = enable absolute tracking
+ T: 1 = enable two finger mode auto correct
+ F: 1 = disable ABS Position Filter
+ R: 1 = enable real hardware resolution

6.2 Native absolute mode 6 byte packet format
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
diff --git a/drivers/input/mouse/elantech.c b/drivers/input/mouse/elantech.c
index ef1cf52f8bb9..230cdcf8e6fe 100644
--- a/drivers/input/mouse/elantech.c
+++ b/drivers/input/mouse/elantech.c
@@ -11,6 +11,7 @@
*/

#include <linux/delay.h>
+#include <linux/dmi.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/input.h>
@@ -831,7 +832,11 @@ static int elantech_set_absolute_mode(struct psmouse *psmouse)
break;

case 3:
- etd->reg_10 = 0x0b;
+ if (etd->set_hw_resolution)
+ etd->reg_10 = 0x0b;
+ else
+ etd->reg_10 = 0x03;
+
if (elantech_write_reg(psmouse, 0x10, etd->reg_10))
rc = -1;

@@ -1331,6 +1336,22 @@ static int elantech_reconnect(struct psmouse *psmouse)
}

/*
+ * Some hw_version 3 models go into error state when we try to set bit 3 of r10
+ */
+static const struct dmi_system_id no_hw_res_dmi_table[] = {
+#if defined(CONFIG_DMI) && defined(CONFIG_X86)
+ {
+ /* Gigabyte U2442 */
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "GIGABYTE"),
+ DMI_MATCH(DMI_PRODUCT_NAME, "U2442"),
+ },
+ },
+#endif
+ { }
+};
+
+/*
* determine hardware version and set some properties according to it.
*/
static int elantech_set_properties(struct elantech_data *etd)
@@ -1389,6 +1410,9 @@ static int elantech_set_properties(struct elantech_data *etd)
*/
etd->crc_enabled = ((etd->fw_version & 0x4000) == 0x4000);

+ /* Enable real hardware resolution on hw_version 3 ? */
+ etd->set_hw_resolution = !dmi_check_system(no_hw_res_dmi_table);
+
return 0;
}

diff --git a/drivers/input/mouse/elantech.h b/drivers/input/mouse/elantech.h
index 036a04abaef7..9e0e2a1f340d 100644
--- a/drivers/input/mouse/elantech.h
+++ b/drivers/input/mouse/elantech.h
@@ -130,6 +130,7 @@ struct elantech_data {
bool jumpy_cursor;
bool reports_pressure;
bool crc_enabled;
+ bool set_hw_resolution;
unsigned char hw_version;
unsigned int fw_version;
unsigned int single_finger_reports;
--
1.9.3