hw.power, machdep.lidaction, machdep.pwraction for macppc

hw.power, machdep.lidaction, machdep.pwraction for macppc

I can now use the power button to power off my macppcs running
OpenBSD.  The new sysctls machdep.lidaction and machdep.pwraction act
like acpibtn(4), but we are missing code to suspend or hibernate a
macppc.  Small kernels (bsd.rd) continue to ignore the power button.

adb(4) sends an environment interrupt when I unplug my PowerBook's AC
or close its lid.  Rename PMU_INT_WAKEUP to PMU_INT_ENVIRONMENT like
other BSDs and Linux.  Handle PMU_ENV_LID_CLOSED as a lid sensor and
PMU_ENV_AC_POWER by setting sysctl hw.power.  Power buttons can either
use PMU_ENV_POWER_BUTTON or go through akbd(4); handle both kinds of
power buttons in the same way.  Other models of macppc, with different
power buttons or lids, might not work yet.  The lid sensor looks like,

$ sysctl hw.sensors
hw.sensors.adb0.indicator0=On (lid open)

kettenis@ warned against calling prsignal() from interrupt context,
and pointed me to task_add(9).