On Tue, Jun 9, 2015 at 4:31 PM, Brent Adam <brentadamdev@xxxxxxxxx> wrote: > 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 | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c > index 6a9b05b..2ee8800 100644 > --- a/drivers/hid/hid-multitouch.c > +++ b/drivers/hid/hid-multitouch.c > @@ -781,6 +781,9 @@ static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi, > */ > if (field->physical == HID_DG_STYLUS) > return 0; > + else if ((field->physical == 0) && > + (field->report->id != td->mt_report_id)) Hmm... That seems wrong. td->mt_report_id is set in mt_touch_input_mapping(), so checking for it before even entering the function seems a little bit odd and activates my bug alert system :) Could you please share the report descriptor of the device you are trying to fix? Ideally, if you could get this by running hid-recorder (http://bentiss.github.io/hid-replay-docs/) that would be even better because you could also record some events from the pen and from the touch. I would also like to see a comment in the code which explains why we need to have a special case to abort earlier. Cheers, Benjamin > + 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 > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
