Input: elantech - touchpad driver miss-recognising logitech mice

Some Logitech mice react to the magic knock like Elantech touchpad would.
This leads to those mice being misdetected as Elantech touchpads.  Add a
version query to elantech_detect() to distinguish the two.

[dtor@mail.ru:
 - lower severity of some messages - when we are not sure yet if
   device is Elantech or not not responding to knock is not an error.
]

Signed-off-by: Arjan Opmeer <arjan@opmeer.net>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 24 insertions, 8 deletions

diff --git a/drivers/input/mouse/elantech.c b/drivers/input/mouse/elantech.c
index b9a25d57bc5e..6ab0eb1ada1c 100644
--- a/drivers/input/mouse/elantech.c
+++ b/drivers/input/mouse/elantech.c
@@ -542,7 +542,7 @@ int elantech_detect(struct psmouse *psmouse, int set_properties)
             ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE11) ||
             ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE11) ||
             ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO)) {
-                pr_err("elantech.c: sending Elantech magic knock failed.\n");
+                pr_debug("elantech.c: sending Elantech magic knock failed.\n");
                 return -1;
         }
 
@@ -551,8 +551,27 @@ int elantech_detect(struct psmouse *psmouse, int set_properties)
          * set of magic numbers
          */
         if (param[0] != 0x3c || param[1] != 0x03 || param[2] != 0xc8) {
-                pr_info("elantech.c: unexpected magic knock result 0x%02x, 0x%02x, 0x%02x.\n",
-                        param[0], param[1], param[2]);
+                pr_debug("elantech.c: "
+                         "unexpected magic knock result 0x%02x, 0x%02x, 0x%02x.\n",
+                         param[0], param[1], param[2]);
+                return -1;
+        }
+
+        /*
+         * Query touchpad's firmware version and see if it reports known
+         * value to avoid mis-detection. Logitech mice are known to respond
+         * to Elantech magic knock and there might be more.
+         */
+        if (synaptics_send_cmd(psmouse, ETP_FW_VERSION_QUERY, param)) {
+                pr_debug("elantech.c: failed to query firmware version.\n");
+                return -1;
+        }
+
+        pr_debug("elantech.c: Elantech version query result 0x%02x, 0x%02x, 0x%02x.\n",
+                 param[0], param[1], param[2]);
+
+        if (param[0] == 0 || param[1] != 0) {
+                pr_debug("elantech.c: Probably not a real Elantech touchpad. Aborting.\n");
                 return -1;
         }
 
@@ -600,8 +619,7 @@ int elantech_init(struct psmouse *psmouse)
         int i, error;
         unsigned char param[3];
 
-        etd = kzalloc(sizeof(struct elantech_data), GFP_KERNEL);
-        psmouse->private = etd;
+        psmouse->private = etd = kzalloc(sizeof(struct elantech_data), GFP_KERNEL);
         if (!etd)
                 return -1;
 
@@ -610,14 +628,12 @@ int elantech_init(struct psmouse *psmouse)
                 etd->parity[i] = etd->parity[i & (i - 1)] ^ 1;
 
         /*
-         * Find out what version hardware this is
+         * Do the version query again so we can store the result
          */
         if (synaptics_send_cmd(psmouse, ETP_FW_VERSION_QUERY, param)) {
                 pr_err("elantech.c: failed to query firmware version.\n");
                 goto init_fail;
         }
-        pr_info("elantech.c: Elantech version query result 0x%02x, 0x%02x, 0x%02x.\n",
-                param[0], param[1], param[2]);
         etd->fw_version_maj = param[0];
         etd->fw_version_min = param[2];