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 <pali.rohar@xxxxxxxxx>
> Tested-by: Pali Rohár <pali.rohar@xxxxxxxxx>
> ---
> 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
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