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 <[email protected]> > Tested-by: Pali Rohár <[email protected]> > --- > 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 -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
