1 files changed, 18 insertions, 4 deletions

diff --git a/drivers/hid/hid-3m-pct.c b/drivers/hid/hid-3m-pct.c
index 2a0d56b7a02b..105743068cca 100644
--- a/drivers/hid/hid-3m-pct.c
+++ b/drivers/hid/hid-3m-pct.c
@@ -24,6 +24,9 @@ MODULE_LICENSE("GPL");
 
 #include "hid-ids.h"
 
+#define MAX_SLOTS               60
+#define MAX_TRKID               59
+
 struct mmm_finger {
         __s32 x, y, w, h;
         __u8 rank;
@@ -31,8 +34,9 @@ struct mmm_finger {
 };
 
 struct mmm_data {
-        struct mmm_finger f[10];
+        struct mmm_finger f[MAX_SLOTS];
         __u8 curid, num;
+        __u8 nexp, nreal;
         bool touch, valid;
 };
 
@@ -93,7 +97,7 @@ static int mmm_input_mapping(struct hid_device *hdev, struct hid_input *hi,
                                         1, 1, 0, 0);
                         return 1;
                 case HID_DG_CONTACTID:
-                        field->logical_maximum = 59;
+                        field->logical_maximum = MAX_TRKID;
                         hid_map_usage(hi, usage, bit, max,
                                         EV_ABS, ABS_MT_TRACKING_ID);
                         return 1;
@@ -133,7 +137,7 @@ static void mmm_filter_event(struct mmm_data *md, struct input_dev *input)
          * we need to iterate on all fingers to decide if we have a press
          * or a release event in our touchscreen emulation.
          */
-        for (i = 0; i < 10; ++i) {
+        for (i = 0; i < MAX_SLOTS; ++i) {
                 struct mmm_finger *f = &md->f[i];
                 if (!f->valid) {
                         /* this finger is just placeholder data, ignore */
@@ -190,6 +194,7 @@ static void mmm_filter_event(struct mmm_data *md, struct input_dev *input)
         } else if (released) {
                 input_event(input, EV_KEY, BTN_TOUCH, 0);
         }
+        input_sync(input);
 }
 
 /*
@@ -223,10 +228,12 @@ static int mmm_event(struct hid_device *hid, struct hid_field *field,
                                 md->f[md->curid].h = value;
                         break;
                 case HID_DG_CONTACTID:
+                        value = clamp_val(value, 0, MAX_SLOTS - 1);
                         if (md->valid) {
                                 md->curid = value;
                                 md->f[value].touch = md->touch;
                                 md->f[value].valid = 1;
+                                md->nreal++;
                         }
                         break;
                 case HID_GD_X:
@@ -238,7 +245,12 @@ static int mmm_event(struct hid_device *hid, struct hid_field *field,
                                 md->f[md->curid].y = value;
                         break;
                 case HID_DG_CONTACTCOUNT:
-                        mmm_filter_event(md, input);
+                        if (value)
+                                md->nexp = value;
+                        if (md->nreal >= md->nexp) {
+                                mmm_filter_event(md, input);
+                                md->nreal = 0;
+                        }
                         break;
                 }
         }
@@ -255,6 +267,8 @@ static int mmm_probe(struct hid_device *hdev, const struct hid_device_id *id)
         int ret;
         struct mmm_data *md;
 
+        hdev->quirks |= HID_QUIRK_NO_INPUT_SYNC;
+
         md = kzalloc(sizeof(struct mmm_data), GFP_KERNEL);
         if (!md) {
                 dev_err(&hdev->dev, "cannot allocate 3M data\n");