[PATCH 4.19 25/58] HID: multitouch: require Finger field to mark Win8 reports as MT

Greg Kroah-Hartman
2021-06-08T18:39:02Z

From: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>

commit a2353e3b26012ff43bcdf81d37a3eaddd7ecdbf3 upstream.

This effectively changes collection_is_mt from
contact ID in report->field
to
(device is Win8 => collection is finger) && contact ID in report->field

Some devices erroneously report Pen for fingers, and Win8 stylus-on-touchscreen
devices report contact ID, but mark the accompanying touchscreen device's
collection correctly

Cc: stable@vger.kernel.org
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Acked-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 | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -588,9 +588,13 @@ static struct mt_report_data *mt_allocat
if (!(HID_MAIN_ITEM_VARIABLE & field->flags))
continue;

- for (n = 0; n < field->report_count; n++) {
- if (field->usage[n].hid == HID_DG_CONTACTID)
- rdata->is_mt_collection = true;
+ if (field->logical == HID_DG_FINGER || td->hdev->group != HID_GROUP_MULTITOUCH_WIN_8) {
+ for (n = 0; n < field->report_count; n++) {
+ if (field->usage[n].hid == HID_DG_CONTACTID) {
+ rdata->is_mt_collection = true;
+ break;
+ }
+ }
}
}