Input: alps - allow up to 2 invalid packets without resetting device
commit 9d720b34 upstream. 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: Pali Rohár <pali.rohar@gmail.com> Tested-by: Pali Rohár <pali.rohar@gmail.com> Reviewed-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
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