On Wed, Sep 7, 2022 at 5:02 PM Andri Yngvason andri@yngvason.is wrote:

This fixes broken atomic checks which cause a race between the release-timer and processing of hid input.

I noticed that contacts were sometimes sticking, even with the "sticky fingers" quirk enabled. This fixes that problem.

Cc: stable@vger.kernel.org Fixes: 9609827458c3 ("HID: multitouch: optimize the sticky fingers timer") Signed-off-by: Andri Yngvason andri@yngvason.is

---

Applied to for-6.1/multitouch in hid.git

Sorry for the delay

Cheers, Benjamin

V1 -> V2: Clarified where the race is and added Fixes tag as suggested by Greg KH V2 -> V3: Fix formatting of "Fixes" tag

drivers/hid/hid-multitouch.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c index 2e72922e36f5..91a4d3fc30e0 100644 --- a/drivers/hid/hid-multitouch.c +++ b/drivers/hid/hid-multitouch.c @@ -1186,7 +1186,7 @@ static void mt_touch_report(struct hid_device *hid, int contact_count = -1;

    /* sticky fingers release in progress, abort */

•   if (test_and_set_bit(MT_IO_FLAGS_RUNNING, &td->mt_io_flags))
  

•   if (test_and_set_bit_lock(MT_IO_FLAGS_RUNNING, &td->mt_io_flags))
            return;
  
    scantime = *app->scantime;
  

@@ -1267,7 +1267,7 @@ static void mt_touch_report(struct hid_device *hid, del_timer(&td->release_timer); }

•   clear_bit(MT_IO_FLAGS_RUNNING, &td->mt_io_flags);
  

•   clear_bit_unlock(MT_IO_FLAGS_RUNNING, &td->mt_io_flags);
  

}

static int mt_touch_input_configured(struct hid_device *hdev, @@ -1699,11 +1699,11 @@ static void mt_expired_timeout(struct timer_list *t) * An input report came in just before we release the sticky fingers, * it will take care of the sticky fingers. */

•   if (test_and_set_bit(MT_IO_FLAGS_RUNNING, &td->mt_io_flags))
  

•   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))
            mt_release_contacts(hdev);
  

•   clear_bit(MT_IO_FLAGS_RUNNING, &td->mt_io_flags);
  

•   clear_bit_unlock(MT_IO_FLAGS_RUNNING, &td->mt_io_flags);
  

}

static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)

2.37.2