Module name: src
Changes by: mpi@cvs.openbsd.org 2014/08/19 06:24:04

Modified files:
sys/dev/pckbc : pms.c

Log message:
Make sure state changes are properly serialized.

When pms(4) is attached to a touchpad it generally presents two different
wsmouse(4) devices: one for the touchpad itself and one for the clitpad
and/or some interleaved packets. But since both devices are writing to
the same pckbc slot, a race can occur if they try to change the state at
the same time.

So prevent two process opening the two /dev/wsmouse* node at the same time
to corrupt the magic sequences needed to enable/disable the touchpad.

ok schadchin@