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HID: multitouch: Fix fields from pen report ID being interpreted for multitouch

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Fields like HID_DG_CONTACTCOUNT are outside of the physical collection,
but within the application collection and report ID.  Make sure to catch
those fields that are not part of the mt_report_id and return 0 so they
can be processed with the pen.  Otherwise, the wrong HID_DG_CONTACTCOUNT
will be applied to cc_index and result in dereferencing a null pointer in
mt_touch_report.

Signed-off-by: Brent Adam <brentadam@smarttech.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>
This commit is contained in:
Brent Adam 2015-06-19 10:53:35 -06:00 committed by Jiri Kosina
parent c5b2b809ce
commit 1cc1cc92c4
1 changed files with 7 additions and 0 deletions
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7
drivers/hid/hid-multitouch.c
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@ -778,9 +778,16 @@ static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
/*
* some egalax touchscreens have "application == HID_DG_TOUCHSCREEN"
* for the stylus.
* The check for mt_report_id ensures we don't process
* HID_DG_CONTACTCOUNT from the pen report as it is outside the physical
* collection, but within the report ID.
*/
if (field->physical == HID_DG_STYLUS)
return 0;
else if ((field->physical == 0) &&
(field->report->id != td->mt_report_id) &&
(td->mt_report_id != -1))
return 0;
if (field->application == HID_DG_TOUCHSCREEN ||
field->application == HID_DG_TOUCHPAD)