Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754371Ab2FTQvR (ORCPT ); Wed, 20 Jun 2012 12:51:17 -0400 Received: from smtprelay-b12.telenor.se ([62.127.194.21]:43298 "EHLO smtprelay-b12.telenor.se" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754019Ab2FTQvQ (ORCPT ); Wed, 20 Jun 2012 12:51:16 -0400 X-SENDER-IP: [85.230.168.62] X-LISTENER: [smtp.bredband.net] X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Ao5QAKT+4U9V5qg+PGdsb2JhbABFihKrPRkBAQEBNzSCGAEBBAEnExwjBQsIAy0ZFCUKGhOIBgm5TBSLI4JqgkhgA5UphWaMfYFU X-IronPort-AV: E=Sophos;i="4.77,445,1336341600"; d="scan'208";a="138945349" From: "Henrik Rydberg" Date: Wed, 20 Jun 2012 18:53:56 +0200 To: "benjamin.tissoires" Cc: Dmitry Torokhov , Jiri Kosina , Stephane Chatty , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/3] HID: hid-multitouch: support arrays for the split of the touches in a report Message-ID: <20120620165356.GA2850@polaris.bitmath.org> References: <1340109594-10732-1-git-send-email-benjamin.tissoires@gmail.com> <1340109594-10732-2-git-send-email-benjamin.tissoires@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1340109594-10732-2-git-send-email-benjamin.tissoires@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1627 Lines: 48 Hi Benjamin, > Win8 certification introduced the ability to transmit two X and two Y per > touch. The specification precises that it must be in an array, with a > report count == 2. > > This test guarantees that we split the touches on the last element > in this array. > > Signed-off-by: Benjamin Tissoires > --- > drivers/hid/hid-multitouch.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c > index 9a3891e..a5ef877 100644 > --- a/drivers/hid/hid-multitouch.c > +++ b/drivers/hid/hid-multitouch.c > @@ -601,7 +601,10 @@ static int mt_event(struct hid_device *hid, struct hid_field *field, > return 0; > } > > - if (usage->hid == td->last_slot_field) > + if (usage->hid == td->last_slot_field && > + usage == &field->usage[field->maxusage - 1]) > + /* we only take into account the last report > + * of a field if report_count > 1 */ This just looks so fragile... The report index should really be amount the arguments to mt_event(). Since we rely on the pointer to reveal the index, why not try something like (usage - &field->usage[0]) == (field->report_count - 1)? At least it shows clearly what we use the point for. > mt_complete_slot(td); > > if (field->index == td->last_field_index > -- > 1.7.10.2 > Thanks, Henrik -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/