Commit be6e2b57 authored by Andri Yngvason's avatar Andri Yngvason Committed by Benjamin Tissoires
Browse files

HID: multitouch: Add memory barriers 



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: 96098274 ("HID: multitouch: optimize the sticky fingers timer")
Signed-off-by: default avatarAndri Yngvason <andri@yngvason.is>
Signed-off-by: default avatarBenjamin Tissoires <benjamin.tissoires@redhat.com>
Link: https://lore.kernel.org/r/20220907150159.2285460-1-andri@yngvason.is
parent a1f76426

drivers/hid/hid-multitouch.c

+4 −4
Original line number Diff line number Diff line
@@ -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)