queue-4.14/hid-wacom-sync-intuosp2_bt-touch-state-after-each-frame-if-necessary.patch

   1 From 69dbdfffef20c715df9f381b2cee4e9e0a4efd93 Mon Sep 17 00:00:00 2001
   2 From: Jason Gerecke <jason.gerecke@wacom.com>
   3 Date: Tue, 7 May 2019 11:53:22 -0700
   4 Subject: HID: wacom: Sync INTUOSP2_BT touch state after each frame if necessary
   5
   6 From: Jason Gerecke <jason.gerecke@wacom.com>
   7
   8 commit 69dbdfffef20c715df9f381b2cee4e9e0a4efd93 upstream.
   9
  10 The Bluetooth interface of the 2nd-gen Intuos Pro batches together four
  11 independent "frames" of finger data into a single report. Each frame
  12 is essentially equivalent to a single USB report, with the up-to-10
  13 fingers worth of information being spread across two frames. At the
  14 moment the driver only calls `input_sync` after processing all four
  15 frames have been processed, which can result in the driver sending
  16 multiple updates for a single slot within the same SYN_REPORT. This
  17 can confuse userspace, so modify the driver to sync more often if
  18 necessary (i.e., after reporting the state of all fingers).
  19
  20 Fixes: 4922cd26f03c ("HID: wacom: Support 2nd-gen Intuos Pro's Bluetooth classic interface")
  21 Cc: <stable@vger.kernel.org> # 4.11+
  22 Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>
  23 Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
  24 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  25
  26 ---
  27  drivers/hid/wacom_wac.c |   10 ++++++++--
  28  1 file changed, 8 insertions(+), 2 deletions(-)
  29
  30 --- a/drivers/hid/wacom_wac.c
  31 +++ b/drivers/hid/wacom_wac.c
  32 @@ -1328,11 +1328,17 @@ static void wacom_intuos_pro2_bt_touch(s
  33                 if (wacom->num_contacts_left <= 0) {
  34                         wacom->num_contacts_left = 0;
  35                         wacom->shared->touch_down = wacom_wac_finger_count_touches(wacom);
  36 +                       input_sync(touch_input);
  37                 }
  38         }
  39
  40 -       input_report_switch(touch_input, SW_MUTE_DEVICE, !(data[281] >> 7));
  41 -       input_sync(touch_input);
  42 +       if (wacom->num_contacts_left == 0) {
  43 +               // Be careful that we don't accidentally call input_sync with
  44 +               // only a partial set of fingers of processed
  45 +               input_report_switch(touch_input, SW_MUTE_DEVICE, !(data[281] >> 7));
  46 +               input_sync(touch_input);
  47 +       }
  48 +
  49  }
  50
  51  static void wacom_intuos_pro2_bt_pad(struct wacom_wac *wacom)