#!/bin/sh

# detect signs of lacking /dev/rtc interrupt
function interrupt_failure () {
  LC_ALL=C /sbin/hwclock --show --debug 2>&1 | \
      grep -q "does not have interrupt functions\|to wait for clock tick > timed out"
 }

if interrupt_failure; then
  echo "--directisa is recommended or required"
else
  echo "/dev/rtc interrupt works OK"
fi