1. 14 Nov, 2014 1 commit
    • Pali Rohár's avatar
      Input: alps - ignore bad data on Dell Latitudes E6440 and E7440 · a7ef82ae
      Pali Rohár authored
      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, but
      instead of reporting PSMOUSE_BAD_DATA, getting into out of sync state,
      getting back in sync with the next byte and spam dmesg we return
      PSMOUSE_FULL_PACKET. If driver is truly out of sync we'll fail the checks
      on the next byte and report PSMOUSE_BAD_DATA then.
      Signed-off-by: default avatarPali Rohár <pali.rohar@gmail.com>
      Tested-by: default avatarPali Rohár <pali.rohar@gmail.com>
      Cc: stable@vger.kernel.org
      Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
      a7ef82ae
  2. 10 Nov, 2014 1 commit
    • Pali Rohár's avatar
      Input: alps - allow up to 2 invalid packets without resetting device · 9d720b34
      Pali Rohár authored
      On some Dell Latitude laptops ALPS device or Dell EC send one invalid byte
      in 6 bytes ALPS packet. In this case psmouse driver enter out of sync
      state. It looks like that all other bytes in packets are valid and also
      device working properly. So there is no need to do full device reset, just
      need to wait for byte which match condition for first byte (start of
      packet). Because ALPS packets are bigger (6 or 8 bytes) default limit is
      small.
      
      This patch increase number of invalid bytes to size of 2 ALPS packets which
      psmouse driver can drop before do full reset.
      
      Resetting ALPS devices take some time and when doing reset on some Dell
      laptops touchpad, trackstick and also keyboard do not respond. So it is
      better to do it only if really necessary.
      Signed-off-by: default avatarPali Rohár <pali.rohar@gmail.com>
      Tested-by: default avatarPali Rohár <pali.rohar@gmail.com>
      Reviewed-by: default avatarHans de Goede <hdegoede@redhat.com>
      Cc: stable@vger.kernel.org
      Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
      9d720b34
  3. 09 Nov, 2014 1 commit
    • Pali Rohár's avatar
      Input: alps - ignore potential bare packets when device is out of sync · 4ab8f7f3
      Pali Rohár authored
      5th and 6th byte of ALPS trackstick V3 protocol match condition for first
      byte of PS/2 3 bytes packet. When driver enters out of sync state and ALPS
      trackstick is sending data then driver match 5th, 6th and next 1st bytes as
      PS/2.
      
      It basically means if user is using trackstick when driver is in out of
      sync state driver will never resync. Processing these bytes as 3 bytes PS/2
      data cause total mess (random cursor movements, random clicks) and make
      trackstick unusable until psmouse driver decide to do full device reset.
      
      Lot of users reported problems with ALPS devices on Dell Latitude E6440,
      E6540 and E7440 laptops. ALPS device or Dell EC for unknown reason send
      some invalid ALPS PS/2 bytes which cause driver out of sync. It looks like
      that i8042 and psmouse/alps driver always receive group of 6 bytes packets
      so there are no missing bytes and no bytes were inserted between valid
      ones.
      
      This patch does not fix root of problem with ALPS devices found in Dell
      Latitude laptops but it does not allow to process some (invalid)
      subsequence of 6 bytes ALPS packets as 3 bytes PS/2 when driver is out of
      sync.
      
      So with this patch trackstick input device does not report bogus data when
      also driver is out of sync, so trackstick should be usable on those
      machines.
      Signed-off-by: default avatarPali Rohár <pali.rohar@gmail.com>
      Tested-by: default avatarPali Rohár <pali.rohar@gmail.com>
      Cc: stable@vger.kernel.org
      Reviewed-by: default avatarHans de Goede <hdegoede@redhat.com>
      Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
      4ab8f7f3
  4. 08 Nov, 2014 3 commits
  5. 06 Nov, 2014 1 commit
  6. 31 Oct, 2014 4 commits
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  17. 04 Oct, 2014 1 commit