#!/bin/bash
#
# New scheme - check interrupt rate on the serial port over 1 sec interval,
# if less than CHARSPERSEC threshold, return
#
# This is actually interrupts, and seem to get ~ 7 chars per interrupt
#
# Modem uses IRQ11
#
CHARSPERSEC=150
NEWINTS=`cat /proc/interrupts | grep '^11:' | awk '{print $2}'`
while true
do
	INTS=$NEWINTS
	sleep 1
	NEWINTS=`cat /proc/interrupts | grep '^11:' | awk '{print $2}'`
#	echo "$NEWINTS - $INTS"
	if expr $NEWINTS '-' $INTS '<' $CHARSPERSEC > /dev/null
	then
		# Char count dropped, make sure line still up
		pppdpid=`/etc/pidrunning pppd`
		if test "$pppdpid" = ""
		then
			# Gone - wait for line up to proceed
			/usr/sbin/waitpppd
			# Wait a while for line to be properly established
			sleep 30
			continue;
		fi 
		break;
	fi
done