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@xxxxxxxxxxxxx> --- 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 6a9b05b..7c81125 100644 --- a/drivers/hid/hid-multitouch.c +++ b/drivers/hid/hid-multitouch.c @@ -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) -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-input" in
