Bug#880203: After suspend&resume, cpufreq/scaling_max_freq is ignored - alternative shell script

[Leon Meier <Leon.Meier@yandex.ru>]

One can also sidestep writing to /tmp in the script in 
/lib/systemd/system-sleep/:

#!/bin/bash
### Ensure that the frequency is restored upon resuming from suspend
# The array to store frequencies:
declare -a frequencies
# Number of processors minus 1:
N=$((`nproc --all`-1))
case "${1}" in
  post)
    # Read the old values:
    for i in `seq 0 $N`; do frequencies[$i]=`cat 
/sys/devices/system/cpu/cpu$i/cpufreq/scaling_max_freq`; done
    # Write a junk value first:
    for i in `seq 0 $N`; do echo 1${frequencies[$i]} > 
/sys/devices/system/cpu/cpu$i/cpufreq/scaling_max_freq; done
    # Let the file kernel digest the previous requests a bit:
    sleep 1
    # Write the old values:
    for i in `seq 0 $N`; do echo ${frequencies[$i]} > 
/sys/devices/system/cpu/cpu$i/cpufreq/scaling_max_freq; done
    ;;
esac

Though this script now avoids writing into /tmp, it's a terribly wild 
hack again invoking bash and other utilities. I'm feeling that it is too 
much an overkill as opposed to doing the right thing in the kernel.