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. Reported-and-tested-by: Breno Leitao <leitao@xxxxxxxxxx> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx> --- drivers/hid/hid-multitouch.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c index ef635964cfe1..a344a3cf5398 100644 --- a/drivers/hid/hid-multitouch.c +++ b/drivers/hid/hid-multitouch.c @@ -642,6 +642,13 @@ static void mt_store_field(struct hid_device *hdev, 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; -- 2.19.2