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HID: multitouch: handle faulty Elo touch device

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commit 81bcbad53b 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: 01eaac7e57 ("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>
This commit is contained in:
Benjamin Tissoires
2019-05-21 15:38:31 +02:00
committed by Greg Kroah-Hartman
parent 9ae306d8db
commit fa212dd5a6
1 changed files with 7 additions and 0 deletions
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7
drivers/hid/hid-multitouch.c
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@@ -641,6 +641,13 @@ 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;