HID: wacom: Initialize MT slots for generic devices at post_parse_hid

If a HID descriptor places HID_DG_CONTACTID before HID_DG_X and HID_DG_Y then
the ABS_X and ABS_Y will not be automatically initialized by the call to
input_mt_init_slots. To ensure that this is not a problem, we relocate that
call to occur after HID parsing has been completed and we've initalized all the
multitouch axes.

Signed-off-by: Jason Gerecke <killertofu@gmail.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

2 files changed, 18 insertions, 3 deletions

diff --git a/drivers/hid/wacom_sys.c b/drivers/hid/wacom_sys.c
index eb5531657e41..872aa0be2e70 100644
--- a/drivers/hid/wacom_sys.c
+++ b/drivers/hid/wacom_sys.c
@@ -13,6 +13,7 @@
 
 #include "wacom_wac.h"
 #include "wacom.h"
+#include <linux/input/mt.h>
 
 #define WAC_MSG_RETRIES         5
 
@@ -236,6 +237,21 @@ static void wacom_usage_mapping(struct hid_device *hdev,
                 wacom_wac_usage_mapping(hdev, field, usage);
 }
 
+static void wacom_post_parse_hid(struct hid_device *hdev,
+                                 struct wacom_features *features)
+{
+        struct wacom *wacom = hid_get_drvdata(hdev);
+        struct wacom_wac *wacom_wac = &wacom->wacom_wac;
+
+        if (features->type == HID_GENERIC) {
+                /* Any last-minute generic device setup */
+                if (features->touch_max > 1) {
+                        input_mt_init_slots(wacom_wac->input, wacom_wac->features.touch_max,
+                                    INPUT_MT_DIRECT);
+                }
+        }
+}
+
 static void wacom_parse_hid(struct hid_device *hdev,
                            struct wacom_features *features)
 {
@@ -270,6 +286,8 @@ static void wacom_parse_hid(struct hid_device *hdev,
                                 wacom_usage_mapping(hdev, hreport->field[i],
                                                 hreport->field[i]->usage + j);
         }
+
+        wacom_post_parse_hid(hdev, features);
 }
 
 static int wacom_hid_set_device_mode(struct hid_device *hdev)
diff --git a/drivers/hid/wacom_wac.c b/drivers/hid/wacom_wac.c
index 7b7a61a9194d..064fd6cf36c6 100644
--- a/drivers/hid/wacom_wac.c
+++ b/drivers/hid/wacom_wac.c
@@ -1381,7 +1381,6 @@ static void wacom_wac_finger_usage_mapping(struct hid_device *hdev,
 {
         struct wacom *wacom = hid_get_drvdata(hdev);
         struct wacom_wac *wacom_wac = &wacom->wacom_wac;
-        struct input_dev *input = wacom_wac->input;
         unsigned touch_max = wacom_wac->features.touch_max;
 
         switch (usage->hid) {
@@ -1400,8 +1399,6 @@ static void wacom_wac_finger_usage_mapping(struct hid_device *hdev,
                                         ABS_MT_POSITION_Y, 4);
                 break;
         case HID_DG_CONTACTID:
-                input_mt_init_slots(input, wacom_wac->features.touch_max,
-                        INPUT_MT_DIRECT);
                 break;
         case HID_DG_INRANGE:
                 break;