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.
