From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751697AbaJCJvd (ORCPT ); Fri, 3 Oct 2014 05:51:33 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36017 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750852AbaJCJvb (ORCPT ); Fri, 3 Oct 2014 05:51:31 -0400 Message-ID: <542E719A.8030509@redhat.com> Date: Fri, 03 Oct 2014 11:51:22 +0200 From: Hans de Goede User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.1.1 MIME-Version: 1.0 To: =?UTF-8?B?UGFsaSBSb2jDoXI=?= , Dmitry Torokhov , Yunkang Tang , Tommy Will CC: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/3] input: alps: For protocol V3, do not process data when last packet's bit7 is set References: <1412329392-5580-1-git-send-email-pali.rohar@gmail.com> <1412329392-5580-3-git-send-email-pali.rohar@gmail.com> In-Reply-To: <1412329392-5580-3-git-send-email-pali.rohar@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 10/03/2014 11:43 AM, Pali Rohár wrote: > Sometimes laptops with closed lid receive invalid ALPS protocol V3 packets with > last bit7 set. > > This happens on Dell Latitude laptops and it looks like it is BIOS bug. Probably > EC does not correctly split keyboard and touchpad PS/2 data and when laptop lid > is closed it adds 0xFF packet into touchpad PS/2 data. > > When last packet's bit7 is set it is invalid ALPS packet. So Do not process it > and drop it with PSMOUSE_FULL_PACKET. > > After testing it looks like this patch fixed problem with reseting mouse (after > series of invalid packets) when laptop lid is closed on Dell Latitude machines. > > Signed-off-by: Pali Rohár > Tested-by: Pali Rohár > --- > drivers/input/mouse/alps.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/drivers/input/mouse/alps.c b/drivers/input/mouse/alps.c > index 1bd5aa1..b1f44d4 100644 > --- a/drivers/input/mouse/alps.c > +++ b/drivers/input/mouse/alps.c > @@ -1179,6 +1179,16 @@ static psmouse_ret_t alps_process_byte(struct psmouse *psmouse) > return PSMOUSE_BAD_DATA; > } > > + if (priv->proto_version == ALPS_PROTO_V3 && psmouse->pktcnt == psmouse->pktsize) { > + // For protocol V3, do not process data when last packet's bit7 is set > + if (psmouse->packet[psmouse->pktcnt - 1] & 0x80) { > + psmouse_dbg(psmouse, "v3 discard packet[%i] = %x\n", > + psmouse->pktcnt - 1, > + psmouse->packet[psmouse->pktcnt - 1]); > + return PSMOUSE_FULL_PACKET; > + } > + } > + I wonder if this should not be PSMOUSE_BAD_DATA as a return value ? I realize that with the 3th patch in place, that will cause an immediate reset, but if your theory is right that this ff gets inserted from the keyboard ps/2 stream, then we actually want a full reset as otherwise we will be out of sync then. > /* Bytes 2 - pktsize should have 0 in the highest bit */ > if ((priv->proto_version < ALPS_PROTO_V5) && > psmouse->pktcnt >= 2 && psmouse->pktcnt <= psmouse->pktsize && > Regards, Hans