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 088d3541c7d3..b96e978a37b7 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)
@@ -1390,6 +1411,9 @@ 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;