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@xxxxxxxxx>
> Tested-by: Pali Rohár <pali.rohar@xxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> ---
> 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!
--
Dmitry
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