linux-kernel - Re: [PATCH v3 3/4] input: alps: For protocol V3, do not process data when last packet's bit7 is set

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Date:	Sun, 9 Nov 2014 12:22:51 +0100
From:	Pali Rohár <pali.rohar@...il.com>
To:	Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc:	Hans de Goede <hdegoede@...hat.com>,
	Yunkang Tang <yunkang.tang@...alps.com>,
	Tommy Will <tommywill2011@...il.com>,
	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 3/4] input: alps: For protocol V3, do not process data when last packet's bit7 is set

On Sunday 09 November 2014 08:50:39 Dmitry Torokhov wrote:
> Hi Pali,
> 
> On Sun, Nov 02, 2014 at 12:25:09AM +0100, Pali Rohár wrote:
> > Sometimes on Dell Latitude laptops psmouse/alps driver
> > receive invalid ALPS protocol V3 packets with bit7 set in
> > last byte. More often it can be reproduced on Dell Latitude
> > E6440 or E7440 with closed lid and pushing cover above
> > touchpad.
> > 
> > If bit7 in last packet byte is set then it is not valid ALPS
> > packet. I was told that ALPS devices never send these
> > packets. It is not know yet who send those packets, it
> > could be Dell EC, bug in BIOS and also bug in touchpad
> > firmware...
> > 
> > With this patch alps driver does not process those invalid
> > packets and drops it with PSMOUSE_FULL_PACKET so psmouse
> > driver does not enter to out of sync state.
> > 
> > This patch fix problem when psmouse driver still resetting
> > ALPS device when laptop lid is closed because of receiving
> > invalid packets in out of sync state.
> > 
> > Signed-off-by: Pali Rohár <pali.rohar@...il.com>
> > Tested-by: Pali Rohár <pali.rohar@...il.com>
> > Cc: stable@...r.kernel.org
> > ---
> > 
> >  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 7c47e97..e802d28 100644
> > --- a/drivers/input/mouse/alps.c
> > +++ b/drivers/input/mouse/alps.c
> > @@ -1181,6 +1181,16 @@ 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 wanted to apply it, but I would like some more data. Could
> you please send me the dmesg with i8042.debug wit this patch
> in place?
> 
> Thanks!

See attachment. It contains debug log from both i8042.debug=1 and 
psmouse.ko with applied all 4 patches.

-- 
Pali Rohár
pali.rohar@...il.com

View attachment "alps-i8042-lid-patches.log" of type "text/x-log" (192890 bytes)

Download attachment "signature.asc " of type "application/pgp-signature" (199 bytes)