HID: multitouch: fix sticky fingers

The sticky fingers quirk (MT_QUIRK_STICKY_FINGERS) was only considering
the case when slots were not released during the last report.
This can be problematic if the firmware forgets to release a finger
while others are still present.

This was observed on the Synaptics DLL0945 touchpad found on the Dell
XPS 9310 and the Dell Inspiron 5406.

Fixes: 4f4001bc76fd ("HID: multitouch: fix rare Win 8 cases when the touch up event gets missing")
Cc: stable@vger.kernel.org
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Signed-off-by: Jiri Kosina <jkosina@suse.com>

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index 513b8673ad8dd7ad135652f787812072d45e6c1a..179dc316b4b518d78bdc900d9fd15756c5eba83e 100644 (file)
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -94,9 +94,8 @@ enum report_mode {
        TOUCHPAD_REPORT_ALL = TOUCHPAD_REPORT_BUTTONS | TOUCHPAD_REPORT_CONTACTS,
 };
 
-#define MT_IO_FLAGS_RUNNING            0
-#define MT_IO_FLAGS_ACTIVE_SLOTS       1
-#define MT_IO_FLAGS_PENDING_SLOTS      2
+#define MT_IO_SLOTS_MASK               GENMASK(7, 0) /* reserve first 8 bits for slot tracking */
+#define MT_IO_FLAGS_RUNNING            32
 
 static const bool mtrue = true;                /* default for true */
 static const bool mfalse;              /* default for false */
@@ -172,7 +171,11 @@ struct mt_device {
        struct timer_list release_timer;        /* to release sticky fingers */
        struct hid_haptic_device *haptic;       /* haptic related configuration */
        struct hid_device *hdev;        /* hid_device we're attached to */
-       unsigned long mt_io_flags;      /* mt flags (MT_IO_FLAGS_*) */
+       unsigned long mt_io_flags;      /* mt flags (MT_IO_FLAGS_RUNNING)
+                                        * first 8 bits are reserved for keeping the slot
+                                        * states, this is fine because we only support up
+                                        * to 250 slots (MT_MAX_MAXCONTACT)
+                                        */
        __u8 inputmode_value;   /* InputMode HID feature value */
        __u8 maxcontacts;
        bool is_buttonpad;      /* is this device a button pad? */
@@ -986,6 +989,7 @@ static void mt_release_pending_palms(struct mt_device *td,
 
        for_each_set_bit(slotnum, app->pending_palm_slots, td->maxcontacts) {
                clear_bit(slotnum, app->pending_palm_slots);
+               clear_bit(slotnum, &td->mt_io_flags);
 
                input_mt_slot(input, slotnum);
                input_mt_report_slot_inactive(input);
@@ -1019,12 +1023,6 @@ static void mt_sync_frame(struct mt_device *td, struct mt_application *app,
        app->left_button_state = 0;
        if (td->is_haptic_touchpad)
                hid_haptic_pressure_reset(td->haptic);
-
-       if (test_bit(MT_IO_FLAGS_ACTIVE_SLOTS, &td->mt_io_flags))
-               set_bit(MT_IO_FLAGS_PENDING_SLOTS, &td->mt_io_flags);
-       else
-               clear_bit(MT_IO_FLAGS_PENDING_SLOTS, &td->mt_io_flags);
-       clear_bit(MT_IO_FLAGS_ACTIVE_SLOTS, &td->mt_io_flags);
 }
 
 static int mt_compute_timestamp(struct mt_application *app, __s32 value)
@@ -1202,7 +1200,9 @@ static int mt_process_slot(struct mt_device *td, struct input_dev *input,
                input_event(input, EV_ABS, ABS_MT_TOUCH_MAJOR, major);
                input_event(input, EV_ABS, ABS_MT_TOUCH_MINOR, minor);
 
-               set_bit(MT_IO_FLAGS_ACTIVE_SLOTS, &td->mt_io_flags);
+               set_bit(slotnum, &td->mt_io_flags);
+       } else {
+               clear_bit(slotnum, &td->mt_io_flags);
        }
 
        return 0;
@@ -1337,7 +1337,7 @@ static void mt_touch_report(struct hid_device *hid,
         * defect.
         */
        if (app->quirks & MT_QUIRK_STICKY_FINGERS) {
-               if (test_bit(MT_IO_FLAGS_PENDING_SLOTS, &td->mt_io_flags))
+               if (td->mt_io_flags & MT_IO_SLOTS_MASK)
                        mod_timer(&td->release_timer,
                                  jiffies + msecs_to_jiffies(100));
                else
@@ -1814,6 +1814,7 @@ static void mt_release_contacts(struct hid_device *hid)
                        for (i = 0; i < mt->num_slots; i++) {
                                input_mt_slot(input_dev, i);
                                input_mt_report_slot_inactive(input_dev);
+                               clear_bit(i, &td->mt_io_flags);
                        }
                        input_mt_sync_frame(input_dev);
                        input_sync(input_dev);
@@ -1836,7 +1837,7 @@ static void mt_expired_timeout(struct timer_list *t)
         */
        if (test_and_set_bit_lock(MT_IO_FLAGS_RUNNING, &td->mt_io_flags))
                return;
-       if (test_bit(MT_IO_FLAGS_PENDING_SLOTS, &td->mt_io_flags))
+       if (td->mt_io_flags & MT_IO_SLOTS_MASK)
                mt_release_contacts(hdev);
        clear_bit_unlock(MT_IO_FLAGS_RUNNING, &td->mt_io_flags);
 }