From: Benjamin Tissoires benjamin.tissoires@redhat.com
commit 81bcbad53bab4bf9f200eda303d7a05cdb9bd73b upstream.
Since kernel v5.0, one single win8 touchscreen device failed. And it turns out this is because it reports 2 InRange usage per touch.
It's a first, and I *really* wonder how this was allowed by Microsoft in the first place. But IIRC, Breno told me this happened *after* a firmware upgrade...
Anyway, better be safe for those crappy devices, and make sure we have a full slot before jumping to the next. This won't prevent all crappy devices to fail here, but at least we will have a safeguard as long as the contact ID and the X and Y coordinates are placed in the report after the grabage.
Fixes: 01eaac7e5713 ("HID: multitouch: remove one copy of values") CC: stable@vger.kernel.org # v5.0+ Reported-and-tested-by: Breno Leitao leitao@debian.org Signed-off-by: Benjamin Tissoires benjamin.tissoires@redhat.com Signed-off-by: Jiri Kosina jkosina@suse.cz Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/hid/hid-multitouch.c | 7 +++++++ 1 file changed, 7 insertions(+)
--- a/drivers/hid/hid-multitouch.c +++ b/drivers/hid/hid-multitouch.c @@ -641,6 +641,13 @@ static void mt_store_field(struct hid_de if (*target != DEFAULT_TRUE && *target != DEFAULT_FALSE && *target != DEFAULT_ZERO) { + if (usage->contactid == DEFAULT_ZERO || + usage->x == DEFAULT_ZERO || + usage->y == DEFAULT_ZERO) { + hid_dbg(hdev, + "ignoring duplicate usage on incomplete"); + return; + } usage = mt_allocate_usage(hdev, application); if (!usage) return;